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Discussion Starter · #1 ·
hi, i'am getting a check engine light on my 97 FORD TAURUS

GL WAGON , the code is :
"P0412 Secondary Air Injection System Switching Valve A

Circuit Malfunction "

i have no idea which part i should replace and ford

dealership is not helpful they want me to pay 98 dollers for

diagnostics but i know the'll just give me the code or

somthing.....in short i dont have much money to spend and

want to try to fix it my self or for cheap.

i have to smog it for registration but i am trying to avoid

the high cost. and i know if i dont fix it it wont pass.

btw, i did reset the check engine light but i came back

again after a few miles

so PLEASE help.
Thanks in advance to all. :(
 

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If you have an electric pump it is more than likely the relay that powers it. Located under the pump itself and mounted on the subframe under the battery.


HM1 CHECK B+ AT SOLID STATE RELAY
Diagnostic Trouble Code (DTC) P0412 indicates EAIR primary circuit fault.

Possible causes:

EAIR circuit open.
EAIR circuit short to power.
AIR bypass solenoid fault.
Solid State Relay fault.
Damaged PCM.
Key off.
Disconnect SSR.
Key on, engine off.
Measure voltage between B+ circuit at SSR vehicle harness connector and battery negative post.
Is voltage greater than 10.5 volts?
Yes No
Supplied voltage is OK, GO to HM2 . GO to HM6 .

HM2 CHECK RESISTANCE OF EAIR CIRCUIT
Key off.
Solid State Relay disconnected.
Disconnect AIR bypass solenoid.
Remove Secondary Air Injection System dedicated fuse temporarily.
Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
Install breakout box, leave PCM disconnected.
Measure resistance between EAIR circuit at SSR vehicle harness connector and Test Pin 70 at the breakout box.
Measure resistance between EAIR circuit at the AIR bypass vehicle harness connector and Test Pin 70 at the breakout box.
Is resistance less than 5.0 ohms?
Yes No
GO to HM3 . SERVICE open EAIR circuit. REMOVE breakout box. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM3 CHECK EAIR CIRCUIT FOR SHORT TO POWER AND GROUND DISCONNECT AIR BYPASS SOLENOID
Key off.
AIR bypass solenoid disconnected.
Solid State Relay disconnected.
PCM disconnected, breakout box installed.
Measure resistance between Test Pins 70 and Test Pin 51, 71, 90, 97 and 103 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
The EAIR harness is OK. GO to HM4 . SERVICE EAIR circuit for short. REMOVE breakout box. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM4 CHECK EAIR CIRCUIT FOR SHORT TO POWER AND GROUND
Key off.
Reconnect AIR bypass solenoid.
Solid State Relay and PCM disconnected, breakout box installed.
Measure resistance between Test Pin 70 and Test Pins 51, 71, 90, 97 and 103 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
EAIR circuit with AIR bypass solenoid OK. GO to HM5 . REPLACE AIR bypass solenoid. REMOVE breakout box. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM5 CHECK EAIR CIRCUIT FOR SHORT TO POWER AND GROUND RECONNECT SOLID STATE RELAY
Key off.
AIR bypass solenoid disconnected.
Reconnect Solid State Relay.
PCM disconnected, breakout box installed.
Measure resistance between Test Pin 70 and Test Pins 51, 71, 90, 97 and 103 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
If P0411 or P1411 are also present:

GO to HM9 .

All others:

GO to HM14 . SERVICE EAIR circuit. REMOVE breakout box. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM6 CHECK RESISTANCE OF B+ CIRCUIT
Key off.
Disconnect Solid State Relay.
Measure resistance between Solid State Relay vehicle harness connector and Secondary Air Injection System dedicated fuse.
Is resistance less than 5.0 ohms?
Yes No
SERVICE Secondary Air Injection System dedicated fuse, then GO to HM8 to check Electric AIR Pump. RECONNECT Solid State Relay. SERVICE open in B+ circuit. RECONNECT Solid State Relay. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM7 VISUALLY INSPECT ELECTRIC AIR PUMP HOSES
DTC P0411/P1411 indicates Secondary Air not detected. In order to test the pump, it must be capable of driving the HO2S lean.

Note: Some applications have one or two AIR Diverter valves.

Possible causes:

Electric AIR Pump fault.
Hose from Electric AIR Pump blocked.
Hose from Electric AIR Pump leak.
AIR Bypass Solenoid stuck open/closed.
AIR Bypass Solenoid leak/blocked.
Key off.
Visually inspect Electric AIR Pump hoses from the Electric AIR Pump to the AIR Diverter valves.
Inspect air hose for cracks, binding, obstructions, water or ice.
Are Electric AIR Pump hoses OK?
Yes No
GO to HM8 . SERVICE by draining all water from hoses or REPLACE damaged parts. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM8 CHECK ELECTRIC AIR PUMP OPERATION
Key off.
Disconnect air hose from either AIR Diverter valve(s).
WARNING: BEWARE OF MOVING VEHICLE COMPONENTS AND HEAT.

Check air flow at the open hose by placing a hand over the outlet of the hose. Caution must be observed while performing this test.
Key on, engine running.
After a 5-second delay, air will be present between 30-90 seconds.
Is air flow present?
Yes No
GO to HM15 to check Electric AIR Pump for water contamination. SERVICE air hose to AIR Diverter valves for leaks or blockage. If OK, GO to HM11 .

HM9 CHECK FOR VACUUM AT AIR DIVERTER VALVES
Key off.
Reconnect PCM.
Disconnect vacuum control line from the AIR Diverter valve(s).
Key on, engine running.
After a 5-second delay, vacuum will be present between 30-90 seconds.
Is vacuum present at the AIR Diverter valve(s)?
Yes No
GO to HM10 . GO to HM30 .

HM10 CHECK AIR DIVERTER VALVE(S) INTEGRITY
Key off.
Reconnect vacuum control line.
Disconnect air tube from AIR Diverter valve(s) outlet side.
Cork off the air tube to prevent exhaust gases from escaping.
Inspect AIR Diverter valve(s) outlets for damage from hot exhaust gases. Service as necessary. Caution must be observed while performing this test.
Key on, engine running.
After a 5-second delay, air will be present between 30-90 seconds.
Is air present from the AIR Diverter valve(s)?
Yes No
GO to Powertrain/Engine Group of the Service Manual to service the exhaust tubes from the AIR Diverter Valve to the exhaust manifold(s). COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . SERVICE hose from Electric AIR Pump to AIR Diverter Valve. If OK, REPLACE the appropriate AIR Diverter Valve(s). RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM11 CHECK EAIR MONITOR CIRCUIT VOLTAGE
Key off.
Disconnect Electric AIR Pump.
Measure voltage between EAIR monitor circuit and ground at the Electric AIR Pump vehicle harness connector.
Key on, engine running.
Is voltage greater than 10.5 volts for 20-30 seconds after a 5 to 10-second delay?
Yes No
GO to HM13 . GO to HM12 .

HM12 CHECK ELECTRIC AIR PUMP GROUND INTEGRITY
Key off.
Electric AIR Pump disconnected.
Measure resistance between Electric AIR Pump GND circuit at the vehicle harness connector and chassis ground.
Is resistance less than 5 ohms?
Yes No
GO to HM19 . SERVICE open ground circuit. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM13 CHECK AIR HOSE TO ELECTRIC AIR PUMP
Key off.
Disconnect inlet air hose.
Visually inspect inlet air hose for binding, obstructions, water or ice to the Electric AIR Pump.
Is the hose integrity OK?




Yes No
REPLACE Electric AIR Pump. ADD RTV to seal the new Electric AIR Pump. REFER to the illustration below. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. SERVICE air hose by draining all water. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM14 CHECK SOLID STATE RELAY OUTPUT
Key off.
AIR Bypass solenoid reconnected.
Solid State Relay reconnected.
Breakout box installed, PCM connected.
Key on.
Measure voltage between Test Pin 5 at the breakout box and chassis ground.
Measure voltage between Test Pin 70 at the breakout box and chassis ground.
Are both greater than 10.5 volts?
Yes No
REPLACE Solid State Relay. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. REPLACE PCM. RECONNECT all components. COMPLETE PCM Reset to clear DTCs.

HM15 CHECK AIR PUMP FOR WATER
Note: Water ingested in the Electric AIR Pump will reduce the life of the pump.

Key off.
Disconnect Electric AIR Pump connector and air hoses.
Carefully tilt Electric AIR Pump in various positions to verify if any water is present.
Is any water present?




Yes No
REPLACE Electric AIR Pump. Water in Electric AIR Pump will reduce the life of the pump. ADD RTV to seal new Electric AIR Pump. REFER to illustration below. COMPLETE PCM Reset to clear DTCs. GO to HM9 .

HM18 CHECK FOR VOLTAGE AT SOLID STATE RELAY
DTC P1413 indicates EAIR monitor circuit is low while the Electric AIR Pump was commanded ON.

Key off.
Disconnect Solid State Relay.
Key on.
Measure voltage between B+ circuit at Solid State Relay vehicle harness connector and chassis ground.
Is voltage greater than 10.5 volts?
Yes No
GO to HM19 . GO to HM24 .

HM19 CHECK EAIR MONITOR CIRCUIT FOR VOLTAGE
Key off.
Reconnect Solid State Relay.
Disconnect Electric AIR Pump.
Measure voltage between EAIR monitor circuit at the Electric AIR Pump vehicle harness connector and chassis ground.
Key on.
Is voltage greater than 10.5 volts?
Yes No
GO to HM23 . If DTC P0411 is present, REPLACE Electric AIR Pump. GO to HM20 .

HM20 CHECK EAIR MONITOR CIRCUIT FOR VOLTAGE, SSR CONNECTED
Key off.
SSR connected.
Electric AIR Pump disconnected. Disconnect PCM, install breakout box.
Measure voltage between Test Pin 5 and chassis ground.
Key on.
Is voltage greater than 10.5 volts?
Yes No
REPLACE PCM. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . GO to HM21 .

HM21 CHECK RESISTANCE OF EAIR DRIVER AND EAIR MONITOR CIRCUITS
Key off.
Disconnect Solid State Relay.
Disconnect PCM. Install breakout box.
Electric AIR Pump disconnected.
Measure resistance between Test Pin 70 at the breakout box and EAIR driver circuit at the Solid State Relay vehicle harness connector.
Measure resistance between Test Pin 5 at the breakout box and EAIR monitor circuit at the Solid State Relay vehicle harness connector.
Measure resistance between EAIR monitor circuit at the Solid State Relay vehicle harness connector and EAIR monitor circuit at the Electric AIR Pump vehicle harness connector.
Is each resistance less than 5.0 ohms?
Yes No
GO to HM22 . SERVICE open EAIR circuit. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM22 CHECK EAIR MONITOR CIRCUIT FOR SHORT TO GROUND
Key off.
Solid State Relay disconnected.
Electric AIR Pump disconnected.
Breakout box installed, PCM disconnected.
Measure resistance between Test Pin 5 and Test Pin 51, 76 and 91 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE Solid State Relay. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . SERVICE EAIR monitor circuit for short to ground. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM23 CHECK EAIR MONITOR CIRCUIT FOR VOLTAGE, ELECTRIC AIR PUMP CONNECTED
Key off.
Reconnect Electric AIR Pump.
Install breakout box. PCM connected.
Key on, engine running.
Measure voltage between Test Pin 5 at the breakout box and chassis ground.
Is voltage greater than 10.5 after the 5 second delay?
Yes No
REPLACE PCM. REMOVE breakout box. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . SERVICE open EAIR monitor circuit. REMOVE breakout box. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM24 CHECK RESISTANCE OF B+ CIRCUIT
Key off.
Solid State Relay disconnected.
Measure resistance between Solid State Relay vehicle harness connector B+ circuit and Solid State Relay dedicated fuse B+ circuit.
Is resistance less than 5 ohms?
Yes No
REPLACE Solid State Relay dedicated fuse. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . SERVICE open B+ circuit. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM25 CHECK RESISTANCE OF EAIR MONITOR CIRCUIT
DTC P1414 indicates Electric AIR Pump commanded off, but PCM indicates Electric AIR Pump is on.

Key off.
Disconnect Solid State Relay.
Disconnect PCM, install breakout box.
Disconnect Electric AIR Pump.
Measure resistance between Test Pin 5 at the breakout box and Electric AIR Pump harness connector.
Is resistance less than 5 ohms?
Yes No
GO to HM26 . SERVICE EAIR monitor circuit for open. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM26 CHECK ELECTRIC AIR PUMP FOR OPEN
Key off.
Electric AIR Pump disconnected.
SSR disconnected.
PCM disconnected.
Measure resistance across Electric AIR Pump terminals at Electric AIR Pump.
Is resistance between 0.5-5.0 ohms?
Yes No
GO to HM27 . REPLACE Electric AIR Pump. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM27 CHECK EAIR MONITOR CIRCUIT FOR SHORT TO POWER, COMPONENTS DISCONNECTED
Key off.
Electric AIR Pump disconnected.
Solid State Relay (SSR) disconnected.
Powertrain Control Module (PCM) disconnected.
Install breakout box.
Key on.
Measure voltage between Test Pin 5 at the breakout box and chassis ground.
Is voltage greater than 10.5 volts?
Yes No
SERVICE EAIR monitor circuit for short to power. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . EAIR Monitor circuit is OK. GO to HM28 .

HM28 CHECK EAIR MONITOR AND EAIR CIRCUITS FOR VOLTAGE
Key off.
Reconnect Solid State Relay and Electric AIR Pump.
Breakout box installed, PCM connected.
Key on, engine running.
Measure voltage between Test Pin 5 at the breakout box and chassis ground.
Measure voltage between Test Pin 70 at the breakout box and chassis ground.
Are both greater than 10.5 volts?
Yes No
REPLACE PCM. REMOVE breakout box. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . REPLACE Solid State Relay. REMOVE breakout box. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM30 CHECK VACUUM HOSE INTEGRITY
Key off.
Check vacuum hose between AIR Bypass solenoid and AIR Diverter valve.
Check for blockage and restrictions.
Check for leaks and cracks.
Check for kinks or disconnects.
Are the above checks OK?
Yes No
GO to HM31 . REPLACE the vacuum line connecting the AIR bypass solenoid to AIR Diverter valve(s). COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM31 CHECK AIR BYPASS SOLENOID ELECTRICAL OPERATION
Key on, engine off.
Connect Scan Tool.
Enter Output Test Mode (OTM). Refer to Section 2A, Diagnostic Methods .
Disconnect AIR bypass solenoid.
Connect digital multimeter to AIR bypass solenoid vehicle harness connector.
Turn the outputs on, then turn outputs off while observing digital multimeter.
Does EAIR circuit voltage cycle greater than 0.5 volt?
Yes No
REMAIN in Output Test Mode. GO to HM32 . GO to HM33 .

HM32 CHECK AIR BYPASS SOLENOID FOR MECHANICAL OPERATION
While remaining in Output Test Mode, reconnect AIR bypass solenoid.
Disconnect source vacuum hose from AIR bypass solenoid.
Apply 53 kPa (16 in-Hg) of vacuum to source side of AIR bypass solenoid.
Turn the outputs on, then turn outputs off.
Was vacuum released?
Yes No
SERVICE vacuum hose from manifold vacuum tree to AIR bypass solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . REPLACE AIR bypass solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM33 CHECK AIR BYPASS SOLENOID RESISTANCE
Key off.
Disconnect AIR bypass solenoid vehicle harness connector.
Measure AIR bypass solenoid resistance.
Is resistance between 50-100 ohms?
Yes No
GO to HM34 , REPLACE AIR bypass solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM34 CHECK B+ CIRCUIT VOLTAGE
Key on, engine off.
AIR bypass solenoid disconnected.
Measure voltage between B+ at the AIR bypass solenoid vehicle harness connector and battery ground.
Is voltage greater than 10.5 volts?
Yes No
GO to HM35 . SERVICE open B+ circuit. RECONNECT AIR bypass solenoid. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM35 CHECK RESISTANCE OF EAIR CIRCUIT
Key off.
AIR bypass solenoid disconnected.
Disconnect Solid State Relay.
Install breakout box, leave PCM disconnected.
Measure resistance between Test Pin 70 at the breakout box and EAIR circuit at the AIR bypass solenoid vehicle harness connector and at the Solid State Relay vehicle harness connector.
Is resistance less than 5.0 ohms?
Yes No
GO to HM36 . SERVICE open EAIR circuit. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM36 CHECK EAIR CIRCUIT FOR SHORT TO GROUND
Key off.
AIR bypass solenoid disconnected.
Solid State Relay disconnected.
Breakout box installed, PCM disconnected.
Disconnect Scan Tool.
Measure resistance between Test Pin 70 and Test Pins 51, 76 and 91 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
GO to HM37 . SERVICE short to ground. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM37 CHECK EAIR CIRCUIT FOR SHORT TO POWER
Key off.
AIR bypass solenoid disconnected.
Solid State Relay disconnected.
Breakout box installed, PCM disconnected.
Measure resistance between Test Pin 70 and Test Pins 71 and 97 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . SERVICE short to power. RECONNECT components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

HM40 DIAGNOSTIC TROUBLE CODE (DTC) P0411
DTC P0411 indicates that Secondary Air is not being diverted when requested.

Possible causes:

Vacuum hoses damaged.
AIR Diverter valve inoperative.
AIR Pump inoperative.
AIR Diverter solenoids damaged.
Visually inspect vacuum lines for disconnects in the AIR system.
Visually inspect for proper vacuum line routing. Refer to VECI decal.
Visually inspect AIR Pump for broken or loose AIR Pump Belt. Refer to HM81 for adjustment/replacement.
Were any of these conditions found?
Yes No
SERVICE as necessary. RERUN Quick Test . GO to HM41 .

HM41 CHECK AIR VACUUM LINES
Carefully check AIR vacuum lines;
From AIR Diverter solenoid to AIR Diverter valve.
From Manifold Vacuum Tree to AIR Diverter solenoids.
Check for obstructions, cracks, kinks and leaks.
Are vacuum lines in good condition?
Yes No
GO to HM42 . SERVICE as necessary. RERUN Quick Test .

HM42 CHECK FOR VACUUM AT THE AIR DIVERTER VALVES
Key off.
Remove control vacuum line from AIR Diverter valves.
Key on, engine running at normal operating temperature.
Check for vacuum at control vacuum line.
Is vacuum present?
Yes No
GO to HM43 . GO to HM63 .

HM43 INSPECT AIR DIVERTER VALVES
Key off.
Disconnect air hose to the AIR check valves at AIR Diverter valve outlet.
Inspect AIR Diverter valve outlet for damage from hot exhaust gas.
Is AIR Diverter valve damaged?
Yes No
REPLACE AIR Diverter valves, then GO to HM60 to inspect AIR Check Valves. GO to HM44 .

HM44 CHECK AIR DIVERTER VALVE DIAPHRAGM
Connect auxiliary vacuum source to one AIR Diverter valve.
Apply 34 kPa (10 in-Hg) vacuum and trap.
Repeat for other AIR Diverter valve.
Does valve hold vacuum?
Yes No
LEAVE vacuum applied. GO to HM45 . REPLACE AIR Diverter valve. VERIFY a symptom no longer exists.

HM45 CHECK AIR DIVERTER OPERATION/FLOW
Key on, engine running.
Increase engine speed to 1500 rpm.
Check for air flow at valve outlet (audibly or by feel).
Is air flow present?
Yes No
GO to HM46 . GO to HM71 to check AIR Pump operation and belt.

HM46 CHECK AIR DIVERTER OPERATION/DUMP
Vent auxiliary vacuum source to 0.
Check that air flow switches from the valve outlet to the dump port or silencer ports (audibly or by feel).
Does the air flow switch?
Yes No
GO to HM47 . REPLACE AIR Diverter valves.

HM47 VISUALLY INSPECT AIR BYPASS VALVE
Key off.
Remove hoses from AIR bypass valve outlets.
Inspect outlets for damage from hot exhaust gases.
Is AIR bypass valve damaged?
Yes No
REPLACE AIR bypass valve, then GO to HM60 for AIR Check Valve. GO to HM48 .

HM48 CHECK FOR VACUUM AT AIR BYPASS VALVE
Note: The next two test steps will require your attention to time.

Key off.
Remove vacuum supply line from vacuum nipple on valve.
Key on, engine running at normal operating temperature.
After engine has started, check for vacuum.
Was vacuum present after a 10-second delay?
Yes No
GO to HM49 . GO to HM63 to VERIFY solenoid AIR bypass vacuum function.

HM49 CHECK AIR BYPASS VALVE DIAPHRAGM
Connect an auxiliary vacuum source to the AIR bypass valve.
Apply 34 kPa (10 in-Hg) vacuum and hold.
Does valve hold vacuum?
Yes No
GO to HM50 . REPLACE AIR bypass valve. VERIFY a symptom no longer exists.

HM50 CHECK FOR AIR SUPPLY AT AIR BYPASS VALVE
Key on, engine running to normal operating temperature.
Remove vacuum supply to AIR bypass valve.
Verify that the air is being supplied to the AIR bypass valve.
Is air present?
Yes No
GO to HM51 . GO to HM71 for AIR Pump operation.

HM51 CHECK FOR AIR AT AIR BYPASS OUTLET(S)
Key on engine running.
Apply 34 kPa (10 in-Hg) of vacuum to AIR bypass valve.
Increase engine speed to 1500 rpm.
Does air flow out of valve outlet?
Yes No
GO to HM52 . REPLACE AIR bypass valve. VERIFY a symptom no longer exists.

HM52 CHECK FOR AIR AT OTHER AIR BYPASS OUTLET
Key on, engine running.
Vent the auxiliary vacuum source to 0.
Does air flow switch from one outlet to the other outlet?
Yes No
GO to HM63 . REPLACE AIR bypass valve. VERIFY a symptom no longer exists.

HM60 VISUALLY INSPECT CHECK VALVE SYSTEM—(EXTERNALLY)
Key off.
Visually inspect secondary air hoses, tubes, control valves and check valves for leaks or external signs of damage (from back flow of hot exhaust gases).
Are hoses and valves intact?
Yes No
GO to HM61 . SERVICE or REPLACE damaged parts including check valve. VERIFY a symptom no longer exists.

HM61 VISUALLY INSPECT HOSES AT VALVES—(INTERNALLY)
Remove hose from check valve inlet.
Inspect inside the hose for damage from hot exhaust gas.
Is the hose clean and undamaged?
Yes No
GO to HM62 . REPLACE hose and check valve. VERIFY a symptom no longer exists.

HM62 INSPECT CHECK VALVE FUNCTION
Note: Check valve may "burble" as air is drawn in.

Key on, engine running.
Listen for escaping exhaust gas or feel for gas (only if engine temperature is at an acceptable level).
Is any exhaust gas escaping?
Yes No
REPLACE check valve. VERIFY a symptom no longer exists. RETURN to Section 3A, Symptom Charts to address other possible causes.

HM63 CHECK AIR BYPASS AND AIR DIVERTER SOLENOIDS ELECTRICAL OPERATION
Connect Scan Tool.
Enter Output Test Mode (OTM) (refer to Section 2A, Diagnostic Methods ).
Disconnect suspect solenoid.
Connect digital multimeter positive test lead to VPWR circuit and negative test lead to signal circuit of suspect vehicle harness connector.
While observing digital multimeter, turn outputs on, then turn outputs off.
Does solenoid circuit cycle voltage?
Yes No
GO to HM64 . REMOVE jumper. GO to HM76 .

HM64 CHECK VACUUM SUPPLY TO AIR DIVERTER/AIR BYPASS SOLENOID
Key off.
Remove vacuum inlet line at suspect (AIR Diverter/AIR Bypass) solenoid.
Start engine and let idle.
Check vacuum at line.
Is vacuum present?
Yes No
REPLACE AIR Bypass or AIR Diverter solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test . GO to HM66 .

HM66 CHECK VACUUM SUPPLY TO RESERVOIR
Key off.
Remove vacuum inlet line at reservoir (For single piece connector, this port is marked MAN or VAC).
Start engine.
Check for vacuum on line.
Is vacuum present?
Yes No
GO to HM68 . If vehicle has a check valve:

GO to HM69 .

If no check valve:

SERVICE vacuum line for leaks, blockage or damage. Verify a symptom no longer exists.

HM68 CHECK RESERVOIR TO HOLD VACUUM
Key off.
Connect vacuum gauge to outlet port (not marked MAN or VAC), keep inlet line connected to vacuum port.
Start engine and run for 30 seconds.
Does gauge increase approximately 50-68 kPa (15 to 20 in-Hg)?
Yes No
REPLACE reservoir outlet hose. If symptom is still present, GO to Symptom Charts, Section 3A for other possible causes. REPLACE vacuum reservoir. VERIFY a symptom no longer exists.

HM69 CHECK AIR FLOW AT CHECK VALVE
Key off.
Remove check valve from vacuum lines (note which direction check valve is installed).
Connect auxiliary vacuum source to black side of check valve.
Connect vacuum gauge to opposite side of check valve.
Apply 54 kPa (16 in-Hg) vacuum to black side.
Does gauge indicate 54 kPa (16 in-Hg)?
Yes No
GO to HM70 . REPLACE Check Valve. VERIFY a symptom no longer exists.

HM70 VERIFY CHECK VALVE'S ABILITY TO HOLD VACUUM
Key off.
Remove auxiliary vacuum source from the check valve.
Does vacuum gauge reading remain above 50 kPa (15 in-Hg) for 10 seconds?
Yes No
GO to Symptom Charts, Section 3A , to address other possible causes. REPLACE Check Valve. VERIFY a symptom no longer exists.

HM71 CHECK BELT TENSION
CAUTION: Do not pry on AIR pump to adjust belt. The aluminum housing is likely to collapse. Refer to AIR Pump drive belt adjustment.

Key off.
Check belt tension and adjust to specification.
Is belt tension adjusted properly?
Yes No
GO to HM72 . ADJUST to specification. GO to HM81 to adjust belt tension.

HM72 CHECK AIR PUMP OPERATION
Key off.
Disconnect air supply hose from AIR Diverter valves.
Check air flow at the pump outlet.
Does air flow increase as the engine speed increases?
Yes No
RETURN to Symptom Chart , Section 3A for other possible causes. GO to HM73 .

HM73 CHECK SILENCER/FILTER FOR OBSTRUCTION
Remove inlet hose (if equipped).
Inspect inlet of silencer/filter for blockage (bugs, leaves, debris).
Is inlet open?
Yes No
REPLACE AIR Pump and VERIFY a symptom no longer exists. REMOVE all debris and VERIFY a symptom no longer exists.

HM75 DIAGNOSTIC TROUBLE CODES (DTCS) P0413, 0414, 0416 AND 0417: CHECK VOLTAGE OF VPWR CIRCUIT
DTCs P0413, 0414, 0416 and 0417 indicate that voltage output for Secondary Air Injection solenoid(s) did not change when activated.

Possible causes:

AIRB/AIRD circuit(s) shorted to power.
AIRB/AIRD circuit(s) open or shorted to ground.
AIR Bypass /AIR Diverter solenoid(s) resistance out of range.
Damaged Powertrain Control Module (PCM).
Disconnect AIR Bypass /AIR Diverter solenoid connector.
Key on, engine off.
Measure voltage between VPWR circuit and battery ground of one solenoid, then repeat for the other solenoid.
Is each voltage greater than 10.5 volts?
Yes No
GO to HM76 . SERVICE open harness circuit. RECONNECT both solenoids. RERUN Quick Test .

HM76 MEASURE AIR BYPASS/AIR DIVERTER SOLENOID RESISTANCE
Key off.
Disconnect both AIR Bypass/AIR Diverter solenoid connectors and measure both solenoid resistances.
Is each resistance between 50 and 100 ohms?
Yes No
GO to HM77 . REPLACE AIR Bypass/AIR Diverter solenoid assembly. RECONNECT both solenoids. RERUN Quick Test .

HM77 CHECK CIRCUIT RESISTANCE
Key off.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
Install breakout box, leave PCM disconnected.
Measure resistance between AIRB circuit at breakout box and AIRB circuit at vehicle harness connector.
Measure resistance between AIRD circuit at the breakout box and AIRD circuit at vehicle harness connector.
Is each resistance less than 5.0 ohms?
Yes No
GO to HM78 . SERVICE open harness circuit. REMOVE breakout box. RECONNECT PCM and both solenoids. RERUN Quick Test .

HM78 CHECK CIRCUIT FOR SHORT TO GROUND
Key off.
Breakout box installed, PCM disconnected.
Disconnect Scan Tool.
Disconnect both AIR Bypass/AIR Diverter solenoids.
Measure resistance between AIRB circuit at the breakout box and Test Pins 51, 91 and 103. Measure resistance between AIRD circuit at the breakout box and Test Pins 51, 91 and 103 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
GO to HM79 . SERVICE short to ground. REMOVE breakout box. RECONNECT PCM and AIR Bypass/AIR Diverter solenoids. RERUN Quick Test .

HM79 CHECK CIRCUIT FOR SHORT TO POWER
Key off.
Breakout box installed, PCM disconnected.
Both AIR Bypass/AIR Diverter solenoids disconnected.
Measure resistance between AIRB circuit at the breakout box and Test Pins 71 and 97. Measure resistance between AIRD circuit at the breakout box and Test Pins 71 and 97 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM. REMOVE breakout box. RECONNECT both solenoids. RERUN Quick Test. SERVICE short to power. REMOVE breakout box. RECONNECT PCM and AIR Bypass/AIR Diverter solenoids. RERUN Quick Test . If DTC is present, REPLACE PCM.

HM81 EXCESSIVE BELT NOISE

Possible causes:

Loose belt.
Seized pump.
Loose pulley.
Loose or broken mounting brackets or bolts.
Inspect for loose belt.
CAUTION: Do not use pry bar to move the AIR pump for belt adjustment.

Use a belt tension gauge to measure belt tension.
Is belt loose?
Yes No
TIGHTEN to specification. VERIFY a symptom no longer exists. GO to HM82 .

HM82 CHECK LOOSE PULLEY, MOUNTING BRACKETS
Check for loose pulley and mounting brackets.
Check for seized AIR Pump .
Check for broken bolts.
Are the above components OK?
Yes No
RETURN to Section 3A, Symptom Charts . For seized pump:

REPLACE pump.

For loose or broken bolts or brackets:

REPLACE components as required and TIGHTEN bolts to 14-17 Nm (120-150 lb-in).

HM83 CHECK FOR EXCESSIVE AIR NOISE

Note: The Secondary Air Injection (AIR) System is not completely noiseless. To determine if the AIR System is the root cause, proceed with the following:

CONDITIONS: Chirps, Squeaks, Ticks, Putt-Putt, Hiss, Rap or Roar.
Disconnect the belt drive only after verifying that the belt tension is correct. (Refer to HM81 .)
Start and run engine.
Did the above conditions disappear?
Yes No
REPLACE any cracked or worn hoses. TIGHTEN mounting bolts to 34 Nm (25 lb-ft). DO NOT OVERTIGHTEN. CHECK AIR Pump fittings. SERVICE as required. ADJUST belt tension to specification. VERIFY a symptom no longer exists. ADJUST belt tension to specification. RETURN to Section 3A, Symptom Charts .




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