Diagnostic Test
WARNING: This page is about a different variant/trim than selected.
- CHECK FOR AN ACTIVE DTC
- Turn the ignition on.
- With the scan tool, read DTCs and record on the repair order.
Is the DTC active or pending?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- CHECK THE (K682) EGR CONTROL 1 CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- Turn the ignition off.
- Disconnect the EGR Valve harness connector.
- Disconnect the PCM C2 harness connector.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K682) EGR Control 1 circuit between the EGR Valve harness connector and the GPEC Adaptor.
Is the resistance below 3.0 Ohms?
Yes
- Go To 3
No
- Repair the (K682) EGR Control 1 circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK THE (K684) EGR CONTROL 2 CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- Measure the resistance of the (K684) EGR Control 2 circuit between the EGR Valve harness connector and the GPEC Adaptor.
Is the resistance below 3.0 Ohms?
Yes
- Go To 4
No
- Repair the (K684) EGR Control 2 circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance of the (K684) EGR Control 2 circuit between the EGR Valve harness connector and the GPEC Adaptor.
- CHECK THE (K682) EGR CONTROL 1 CIRCUIT AND (K684) EGR CONTROL 2 CIRCUIT FOR A SHORT TO VOLTAGE NOTE:
If one of the EGR Control circuits is shorted to another 12 volt supply, the internal PCM driver may get damaged causing the an open on the EGR Control circuitry.
- Check for continuity between the:
- (K682) EGR Control 1 circuit and all other circuits at the GPEC Adaptor.
- (K684) EGR Control 2 circuit and all other circuits at the GPEC Adaptor.
Is there continuity between the EGR Control circuits and any other circuits?
Yes
- Repair the short between the EGR Control circuit and the circuit that showed continuity.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 5
- Check for continuity between the:
- CHECK THE EGR VALVE FOR PROPER OPERATION
- Replace the EGR Valve in accordance with the Service Information. Refer to VALVE, EXHAUST GAS RECIRCULATION (EGR), REMOVAL . The EGR VALVE REPLACED routine must be performed after replacing or cleaning the EGR Valve to reset the zero learn position. Failure to do so will cause a false failure and the P1404 DTC to set. With the scan tool, perform the EGR VALVE REPLACED routine.
- Reconnect the EGR Valve harness connector.
- Reconnect the PCM C2 harness connector.
- Turn the ignition on.
- With the scan tool, erase DTCs.
- Start the engine and test drive the vehicle.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To 6
No
- Repair is complete.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all PCM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Check for spread terminals and verify proper terminal tension.
Repair any conditions that are found.
- Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Test drive or operate the vehicle in accordance with the when monitored and set conditions.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- The wiring or poor connection problem has been repaired.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .