P2146 Diagnostics Please

[RKerner]

Does anyone have access to the diagnostic tree for code P2146? It just happened on the way home from town. Is the power side of the front 3 injectors fed from the fuse/relay center or from the ECM (PCM)?



Thanks in advance.

 

[JIWright]

P2146-BANK 1 (CYLINDERS 1-3) SHORTED HIGH OR LOW









For a complete wiring diagram Refer to Section 8W.



When Monitored:

While the engine is running.



Set Condition:

A circuit failure detected at cylinders 1,2, or 3 or any combination of cylinders 1,2, or 3.



Possible Causes

OTHER DTC'S

HIGH SIDE DRIVER CIRCUIT OPEN

LOW SIDE DRIVER CIRCUIT OPEN

HIGH SIDE DRIVER SHORTED TO LOW SIDE DRIVER

HIGH SIDE DRIVERS SHORTED LOW

LOW SIDE DRIVER CIRCUIT SHORTED OTHER LOW SIDE DRIVER CIRCUIT

LOW SIDE DRIVERS SHORTED LOW

HIGH SIDE DRIVER SHORTED TO VOLTAGE

LOW SIDE DRIVER SHORTED TO VOLTAGE

LOW SIDE DRIVER CIRCUIT SHORTED IN INJECTOR HARNESS

INJECTOR

INJECTOR HARNESS

INTERMITTENT CONDITION

ECM





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)



Diagnostic Test

1. OTHER DTC'S



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With the scan tool, read DTCs.



Do you have any combination of DTC's P0201, P0202, or P0203?



Yes

Repair other DTC's first.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)



No

Go To 2







2. HIGH SIDE DRIVER CIRCUIT OPEN



--------------------------------------------------------------------------------







Turn the ignition off.

Disconnect the ECM harness connectors.

Disconnect the Injector 1-3 harness connector.



NOTE: Check connectors - Clean/repair as necessary.





Measure the resistance of the injector high side driver circuit between the Bank 1 high side driver circuit in the ECM harness connector and the high side driver circuit in the injector harness connectors for cylinders 1-3.



Is the resistance less than 10 Ohms?



Yes

Go To 3



No

Repair the open high side driver circuit from ECM harness connector to the Injector harness connector.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







3. LOW SIDE DRIVER CIRCUIT OPEN



--------------------------------------------------------------------------------







Measure the resistance of the #1,#2, and #3 injector low side driver circuits between the ECM harness connector and the injector harness connectors.



Is the resistance less than 10 Ohms?



Yes

Go To 4



No

Repair the open low side driver circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







4. HIGH SIDE DRIVER SHORTED TO LOW SIDE DRIVER



--------------------------------------------------------------------------------







Measure the resistance between the Bank 1 high side driver circuit at the ECM harness connector and the low side driver circuit for injectors 1-3 at the ECM harness connector.



Is the resistance more than 100k Ohms?



Yes

Go To 5



No

Repair the High side circuit shorted to the low side circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







5. HIGH SIDE DRIVERS SHORTED LOW



--------------------------------------------------------------------------------







Measure the resistance of the injector harness connector high side driver circuits to battery negative for injectors 1-3.



Is the resistance more than 100k Ohms?



Yes

Go To 6



No

Repair the High side driver shorted low in the harness.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







6. LOW SIDE DRIVERS SHORTED LOW



--------------------------------------------------------------------------------







Measure the resistance of the injector harness connector Low side driver circuits to battery negative for injectors 1-3.



Is the resistance more than 100k Ohms?



Yes

Go To 7



No

Repair the Low side driver shorted low in the harness.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







7. HIGH SIDE DRIVER SHORTED TO VOLTAGE



--------------------------------------------------------------------------------







Measure the voltage between the high side driver circuit in the engine harness and battery negative.



Is the voltage less than 1 volt?



Yes

Go To 8



No

Repair the high side driver shorted to voltage.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







8. LOW SIDE DRIVER SHORTED TO VOLTAGE



--------------------------------------------------------------------------------







Measure the voltage between the low side driver circuit in the engine harness and battery negative for cylinders 1-3.



Is the voltage less than 1 volt?



Yes

Go To 9



No

Repair the low side driver shorted to voltage.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







9. LOW SIDE DRIVER CIRCUIT SHORTED OTHER LOW SIDE DRIVER CIRCUIT



--------------------------------------------------------------------------------







Measure the resistance of each of the Bank 1 low side driver circuit to all other Bank 1 low side driver circuits at the ECM harness connector.



Is the resistance greater than 100k ohms?



Yes

Go To 10



No

Repair Low side driver circuit shorted to other Low side driver circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







10. LOW SIDE DRIVER CIRCUIT SHORTED IN INJECTOR HARNESS



--------------------------------------------------------------------------------







Reconnect the disconnected injector harness connector.

Measure the resistance of each of the Bank 1 low side driver circuit to all other Bank 1 low side driver circuit at the ECM harness connector.



Is the resistance greater than 100k ohms?



Yes

Go To 11



No

Replace the injector harness.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







11. INJECTOR CIRCUITS SHORTED INSIDE ENGINE



--------------------------------------------------------------------------------







Disconnect the injector through head harness connector.

Measure the resistance of each injector from the through head connector.



NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.







Is the resistance greater than 0 ohms and less than 1 ohm?



Yes

Go To 12



No

Go To 14







12. INJECTOR



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Disconnect the pigtail nuts from injectors 1-3.



NOTE: Check connectors - Clean/repair as necessary.





Measure the resistance between the solenoid posts of each injector.



NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.







Is the resistance less than 1 ohm and greater than 0 ohms?



Yes

Go To 13



No

Replace the fuel injector or injectors.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)







13. INJECTOR HARNESS



--------------------------------------------------------------------------------







Measure resistance of each circuit in the injector harness from pigtail side to injector harness connector.



Is resistance above 1 ohm?



Yes

Replace the injector harness.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)



No

Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)







14. ECM



--------------------------------------------------------------------------------

Reconnect the all injector pig tails harness connector.

Reconnect the ECM harness connector.

Reconnect the Injector harness connector.

Start the engine.

With the scan tool, read DTCs.



Did the DTC return?



Yes

Replace and program the ECM in accordance with the Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)



No

Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

 

[RKerner]

Thanks for the quick response. I verified that the front 3 cylinders dropped and wiggled the 1-3 harness connector and it didn't change how it ran. Both FCU fuses are good, a quick test light check while running shows a switching signal on all 4 wires (not sure about that as I thought only 3 would be switching). Looks like I need to get a manual to look at the wiring diagram to ring out the harness to the injectors. BTW, no boxes and no other codes when this occurs.

 

[sag2]

It is usually the valve cover gasket, but run the diagnostic to be sure. Pay close attention to the connectors. Also in step 2 and 3 (if you get to them) instead of using an ohm meter you should really load test them using a high current bulb like a halogen headlamp bulb.

Also keep in mind if the fault is stored and not active the diagnostic will always lead you to the ECM if you ignore the instructions and continue on with the procedure. Virtually all Chrysler fault tree's only are good with an active fault. Stored faults mean the problem was intermittent and is not currently there.

 

[RKerner]

Connectors are good, high side driver wiring good, resistance across the injectors is good, #1 injector is "leaky" to ground. I removed the wires from the injector and verified it has a path from the terminal to ground. What may be the ramifications of running this thing much longer? When it shorts, it knocks out 3 cylinders as I can get boost but can't break 300 degrees on EGT. I'm not seeing where the ECM is protected from this type of failure since it does the power switching.



Would now be a good time to replace nozzles and one injector?