I recently replaced a fuel pump. The car drove fine untill today. It gave me a very low rough idle and almost cut out on me. The check engine light came on so I stop at the auto zone that was right up the street. The computer was putting out the error code P1235. I have done some googleing and found what the error code is for I just can't find a way to fix it.
Shodrin
P1235 Fuel Pump Control out Of Range (Fuel Pump Driver Module/VLCM) *
from our trouble code index.
from our trouble code index.
QUOTE (sable23 @ Dec 28 2009, 05:25 PM) index.php?act=findpost&pid=776015
I found that much from google. What i need to know is how to fix it. I have no idea where this module is.
here you go;
KB30 DTC P1235 OR P1236: IS DTC P1235 OR P1236 PRESENT IN KEY ON ENGINE OFF OR ENGINE RUNNING SELF TEST?
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.
Note: For LS6/LS8 and Thunderbird, the FPDM functions are incorporated in the Rear Electronics Module (REM). In the following steps, if directed to perform an action with the FPDM, complete the action with the REM. Refer to the pin numbers in the beginning of this pinpoint test.
Is DTC P1235 or P1236 present in Key On Engine Off or Engine Running Self-Test?
Yes No
A hard fault is present. GO to KB31 to check the FP circuit. DTC P1235 or P1236 is intermittent.
For LS6/LS8 and Thunderbird :
GO to KB42 .
All others :
GO to KB45 .
KB31 CHECK FOR OPEN FP CIRCUIT BETWEEN PCM AND FPDM
Disconnect FPDM.
Disconnect PCM.
Measure resistance of FP circuit between PCM harness connector pin and the FPDM harness connector.
Is resistance less than 5.0 ohms?
Yes No
GO to KB32 . REPAIR open circuit.
KB32 CHECK FP CIRCUIT FOR SHORT TO POWER IN HARNESS
Key on, engine off.
Measure voltage between FP circuit at PCM harness connector pin and ground.
Is voltage less than 1.0 volt?
Yes No
KEY OFF. GO to KB33 . REPAIR short circuit.
KB33 CHECK FP CIRCUIT FOR SHORT TO GROUND IN HARNESS
Disconnect scan tool from DLC.
Measure resistance between FP circuit at PCM harness connector pin and ground.
Is resistance greater than 10,000 ohms?
Yes No
For LS6/LS8 and Thunderbird :
GO to KB36 .
All others :
GO to KB34 . REPAIR short circuit.
KB34 CHECK FP CIRCUIT IN FPDM
Reconnect FPDM.
Key on, engine off.
Measure voltage between FP circuit at PCM harness connector pin and ground.
Is voltage between 4.5 and 5.5 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)). REPLACE FPDM.
KB36 CHECK FPF PID
Key on, engine off.
Access the FP and FPF PIDs on the scan tool (the FP PID may be used in the next step).
While viewing the FPF PID for 20 seconds, check if the FPF PID will indicate YES. The FPF PID may read NO in the 20 seconds, but will change back to YES.
Does the FPF PID indicate YES within 20 seconds?
Yes No
GO to KB40 . GO to KB37 .
KB37 CHECK FP PID
Does the FP PID indicate between 70 and 80%?
Yes No
GO to KB38 . TURN KEY OFF then back ON. Wait 5 seconds. REPEAT test step. If result is now YES, follow YES result. If result is still NO, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)).
KB38 ACCESS REM PIDS AND CHECK PWM_DC1 PID
Access the PWM_DC1 PID from the REM menu (the PWM_DC1 PID indicates the signal sent to the REM from the PCM on the FP circuit).
Does the PWM_DC1 PID indicate between 70 and 80%?
Yes No
KEY OFF. No fault indicated. Disregard DTC P1235 or P1236. RETURN to Section 3 where DTC was received and proceed as directed. REPLACE REM.
KB40 CHECK REM CIRCUITRY VOLTAGE ON FP CIRCUIT AT PCM
Key off.
Disconnect PCM connector A.
Key on, engine off.
Measure voltage between Pin A58 at the PCM harness connector A and ground.
Is voltage greater than 8 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)). REPLACE REM.
KB42 CHECK FP CIRCUIT FOR INTERMITTENT CONCERNS
Key on, engine off.
Access the REM PID access menu on the scan tool.
Access the PWM_DC1 PID from the REM menu (the PWM_DC1 PID indicates the signal sent to the REM from the PCM on the FP circuit).
Observe the PWM_DC1 PID for indication of a fault while completing the following (the PID value will change when a fault is detected):
Shake, wiggle and bend the FP circuit between the PCM (Pin A58) and REM (Pin J2-19).
Is a fault indicated?
Yes No
ISOLATE fault and REPAIR as necessary. KEY OFF. Unable to duplicate or identify fault at this time. GO to Z1 with the following data: PWM_DC1 PID (REM menu), FP PID (PCM menu, the FP PID is the signal the PCM is sending to the REM).
KB45 CHECK FP CIRCUIT FOR INTERMITTENT OPENS OR SHORTS
Key on, engine off.
Access FPM PID.
Note: With no fault detected, the FPDM will send a 50% duty cycle signal (all OK) to the PCM on the FPM circuit. Depending on scan tools, the FPM PID may display 50%, or a random value that is fluctuating between 85 and 115%.
Observe the FPM PID for an indication of a fault while completing the following (look for the FPM PID to change from the 50% value, or to stop fluctuating):
Shake, wiggle, bend the FP circuit between FPDM and the PCM.
Lightly tap on the FPDM (to simulate road shock).
Is a fault indicated?
Yes No
ISOLATE fault and REPAIR as necessary. KEY OFF. Unable to duplicate or identify fault at this time.GO to Z1 .
KB30 DTC P1235 OR P1236: IS DTC P1235 OR P1236 PRESENT IN KEY ON ENGINE OFF OR ENGINE RUNNING SELF TEST?
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.
Note: For LS6/LS8 and Thunderbird, the FPDM functions are incorporated in the Rear Electronics Module (REM). In the following steps, if directed to perform an action with the FPDM, complete the action with the REM. Refer to the pin numbers in the beginning of this pinpoint test.
Is DTC P1235 or P1236 present in Key On Engine Off or Engine Running Self-Test?
Yes No
A hard fault is present. GO to KB31 to check the FP circuit. DTC P1235 or P1236 is intermittent.
For LS6/LS8 and Thunderbird :
GO to KB42 .
All others :
GO to KB45 .
KB31 CHECK FOR OPEN FP CIRCUIT BETWEEN PCM AND FPDM
Disconnect FPDM.
Disconnect PCM.
Measure resistance of FP circuit between PCM harness connector pin and the FPDM harness connector.
Is resistance less than 5.0 ohms?
Yes No
GO to KB32 . REPAIR open circuit.
KB32 CHECK FP CIRCUIT FOR SHORT TO POWER IN HARNESS
Key on, engine off.
Measure voltage between FP circuit at PCM harness connector pin and ground.
Is voltage less than 1.0 volt?
Yes No
KEY OFF. GO to KB33 . REPAIR short circuit.
KB33 CHECK FP CIRCUIT FOR SHORT TO GROUND IN HARNESS
Disconnect scan tool from DLC.
Measure resistance between FP circuit at PCM harness connector pin and ground.
Is resistance greater than 10,000 ohms?
Yes No
For LS6/LS8 and Thunderbird :
GO to KB36 .
All others :
GO to KB34 . REPAIR short circuit.
KB34 CHECK FP CIRCUIT IN FPDM
Reconnect FPDM.
Key on, engine off.
Measure voltage between FP circuit at PCM harness connector pin and ground.
Is voltage between 4.5 and 5.5 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)). REPLACE FPDM.
KB36 CHECK FPF PID
Key on, engine off.
Access the FP and FPF PIDs on the scan tool (the FP PID may be used in the next step).
While viewing the FPF PID for 20 seconds, check if the FPF PID will indicate YES. The FPF PID may read NO in the 20 seconds, but will change back to YES.
Does the FPF PID indicate YES within 20 seconds?
Yes No
GO to KB40 . GO to KB37 .
KB37 CHECK FP PID
Does the FP PID indicate between 70 and 80%?
Yes No
GO to KB38 . TURN KEY OFF then back ON. Wait 5 seconds. REPEAT test step. If result is now YES, follow YES result. If result is still NO, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)).
KB38 ACCESS REM PIDS AND CHECK PWM_DC1 PID
Access the PWM_DC1 PID from the REM menu (the PWM_DC1 PID indicates the signal sent to the REM from the PCM on the FP circuit).
Does the PWM_DC1 PID indicate between 70 and 80%?
Yes No
KEY OFF. No fault indicated. Disregard DTC P1235 or P1236. RETURN to Section 3 where DTC was received and proceed as directed. REPLACE REM.
KB40 CHECK REM CIRCUITRY VOLTAGE ON FP CIRCUIT AT PCM
Key off.
Disconnect PCM connector A.
Key on, engine off.
Measure voltage between Pin A58 at the PCM harness connector A and ground.
Is voltage greater than 8 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM)). REPLACE REM.
KB42 CHECK FP CIRCUIT FOR INTERMITTENT CONCERNS
Key on, engine off.
Access the REM PID access menu on the scan tool.
Access the PWM_DC1 PID from the REM menu (the PWM_DC1 PID indicates the signal sent to the REM from the PCM on the FP circuit).
Observe the PWM_DC1 PID for indication of a fault while completing the following (the PID value will change when a fault is detected):
Shake, wiggle and bend the FP circuit between the PCM (Pin A58) and REM (Pin J2-19).
Is a fault indicated?
Yes No
ISOLATE fault and REPAIR as necessary. KEY OFF. Unable to duplicate or identify fault at this time. GO to Z1 with the following data: PWM_DC1 PID (REM menu), FP PID (PCM menu, the FP PID is the signal the PCM is sending to the REM).
KB45 CHECK FP CIRCUIT FOR INTERMITTENT OPENS OR SHORTS
Key on, engine off.
Access FPM PID.
Note: With no fault detected, the FPDM will send a 50% duty cycle signal (all OK) to the PCM on the FPM circuit. Depending on scan tools, the FPM PID may display 50%, or a random value that is fluctuating between 85 and 115%.
Observe the FPM PID for an indication of a fault while completing the following (look for the FPM PID to change from the 50% value, or to stop fluctuating):
Shake, wiggle, bend the FP circuit between FPDM and the PCM.
Lightly tap on the FPDM (to simulate road shock).
Is a fault indicated?
Yes No
ISOLATE fault and REPAIR as necessary. KEY OFF. Unable to duplicate or identify fault at this time.GO to Z1 .
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
