Let's see ....air bags, brake fluid... :headscratch:
Air bag codes are usually from bad sensors.
DTC B1941: RH PRIMARY CRASH SENSOR FEED/RETURN CIRCUIT OPEN — LAMP FAULT CODE 41
Normal Operation
The voltage at Pin C276-16, Circuit 621 (W/Y) is set by the air bag diagnostic monitor to be slightly less than battery voltage. Circuit 621 (W/Y) is connected to Circuit 624 (Y/W) inside RH primary crash sensor. Therefore, the voltage at Circuit 624 (Y/W) and air bag diagnostic monitor Pin C277-24 should be the same as the voltage at air bag diagnostic monitor Pin C276-16, Circuit 621 (W/Y).
The air bag diagnostic monitor periodically pulls the voltage at Pin C276-16, Circuit 621 (W/Y) low to verify the connection to Pin C277-24, Circuit 624 (Y/W). If the voltage at Pin C277-24, Circuit 624 (Y/W) does not pull low as a result of this test, the air bag diagnostic monitor will store in memory DTC B1941 and flash lamp fault code 41 on the air bag indicator. If the connection between Pins C276-16, Circuit 621 (W/Y) and C277-24, Circuit 624 (Y/W) is later serviced, DTC B1941 will be stored in memory.
Possible Causes
Failure to get low voltage at Pin C277-24, Circuit 624 (Y/W) during the test can be caused by:
an open circuit in the wiring harness in either Circuit 621 (W/Y) or Circuit 624 (Y/W).
an open circuit inside RH primary crash sensor across Circuit 621 (W/Y) or Circuit 624 (Y/W).
a short to battery or ignition voltage in any of the Circuits 621 (W/Y), 619 (PK/W), 624 (Y/W), 625 (Y/LG).
B1941-1 CHECK FOR HARD OR INTERMITTENT DTC
Connect Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent to DLC located under the instrument panel.
Perform on-demand self-test as described.
Was DTC B1941 retrieved?
Yes No
NOTE: This is a hard fault. The fault condition is still present. This fault may not be cleared until it is corrected and the DTC no longer is retrieved during on-demand self-test.
GO to B1941-2 . NOTE: This is an intermittent fault. The fault condition is not present at this time.
GO to B1941-6 .
B1941-2 MEASURE RESISTANCE
Deactivate system.
Disconnect air bag diagnostic monitor.
Set ohmmeter to 200 ohm scale or AUTO.
Zero ohmmeter by touching leads together and record resistance reading.
Measure resistance between air bag diagnostic monitor harness connector Pins C276 , Circuit 621 (W/Y) and C277 , Circuit 624 (Y/W). Subtract the reading found when zeroing ohmmeter.
Is resistance less than 2 ohms?
Yes No
GO to B1941-3 . GO to B1941-4 .
B1941-3 CHECK FOR SHORTS TO BATTERY
With air bag diagnostic monitor disconnected, turn ignition switch to RUN position.
Measure the voltage between the following air bag diagnostic monitor harness pins and ground:
Pin C276 , Circuit 619 (PK/W)
Pin C276 , Circuit 621 (W/Y)
Pin C277 , Circuit 625 (Y/LG)
Pin C277 , Circuit 624 (Y/W)
Is the voltage greater than zero on any of these wires?
Yes No
SERVICE short to B+ on appropriate circuit. GO to B1941-10 . REPLACE air bag diagnostic monitor. RECONNECT system. VERIFY system. GO to B1941-10 .
B1941-4 CHECK SENSOR RESISTANCE
Access RH primary crash sensor.
Disconnect sensor from harness.
Measure resistance between Circuit 621 (W/Y) and 624 (Y/W) wires in sensor side of connector.
Is the resistance reading less than 2 ohms?
Yes No
GO to B1941-5 . REPLACE RH primary crash sensor. VERIFY system. GO to B1941-10 .
B1941-5 CHECK CIRCUIT 621 (W/Y) FOR OPEN
Disconnect air bag diagnostic monitor.
Disconnect RH primary crash sensor.
Using an ohmmeter, check the resistance of Circuit 621 (W/Y) between RH primary crash sensor connector and Pin C276 of air bag diagnostic monitor.
Is resistance less than 3 ohms?
Yes No
SERVICE Circuit 624 (Y/W) for an open. RECONNECT system. VERIFY system. REACTIVATE system. GO to B1941-10 . SERVICE Circuit 621 (W/Y) for an open. RECONNECT system. VERIFY system. REACTIVATE system. GO to B1941-10 .
B1941-6 CHECK FOR SERVICED DTCS
Deactivate system.
Has a DTC B1941 just been serviced?
Yes No
GO to B1941-10 . GO to B1941-7 .
B1941-7 CHECK WIRES
NOTE: An intermittent open in these circuits may lead to a DTC B1941.
Visually inspect the wires, crimps, connectors, etc., on Circuits 621 (W/Y) and 624 (Y/W). Look for signs of poor connections.
Are any concerns noticed?
Yes No
SERVICE any concerns found. GO to B1941-10 . GO to B1941-8 .
B1941-8 CHECK FOR SHORT TO BATTERY
NOTE: An intermittent short to battery or ignition on any of these wires may cause a DTC B1941 and a DTC B1942.
Visually inspect Circuits:
621 (W/Y)
619 (PK/W)
624 (Y/W)
625 (Y/LG)
Are any concerns noticed?
Yes No
SERVICE any concerns if found. GO to B1941-10 . GO to B1941-9 .
B1941-9 CHECK SENSOR
Locate and visually inspect RH primary crash sensor. Look for signs of corrosion.
Are any concerns noticed?
Yes No
REPLACE RH primary crash sensor. If significant corrosion is noticed, GO to B1941-10 . RE-EXAMINE fault code description and schematic. LOOK for causes of intermittent opens or high resistance in the appropriate circuits. ATTEMPT to recreate hard faults by driving vehicle, flexing wire harnesses, etc., cycling ignition switch frequently. SERVICE any intermittent problems if found. GO to B1941-10 .
B1941-10 CHECK FOR OTHER DTCS
NOTE: Do not clear any DTCs until all DTCs are addressed.
Connect NGS 070-00500 or equivalent to DLC located under the instrument panel.
Select: IABM
Select: Diagnostic Test Modes
Select: Retrieve/Clear continuous DTCs
Were any other DTCs retrieved?
Yes No
NOTE: Do not clear any DTCs until all DTCs are addressed.
REFER to Air Bag Diagnostic Monitor Diagnostic Trouble Code (DTC) Index Table and GO to proper pinpoint test to continue diagnostics. REACTIVATE system as described. CLEAR all DTCs as described.