Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) ACTIVE DTC
Ignition on, engine not running.

With a scan tool, read DTCs.

Is the DTC active at this time?

Yes
1. Go To step 2).
No
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
2) EVAP PURGE SOLENOID OPERATION

Fig 1: Checking EVAP Purge Solenoid
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the EVAP Purge Solenoid harness connector.

Ignition on, engine not running.

Using a 12-volt test light, jump across the Evap Purge Solenoid harness connector.

With the scan tool, actuate the EVAP Purge Solenoid.

Does the test light flash on and off?

Yes
1. Go To step 3).
No
1. Go To step 7).
3) EVAP PURGE SOLENOID LEAKS/STUCK OPEN
Turn the ignition off.

Connect the Evap Purge Solenoid harness connector.

Disconnect the vacuum hoses at the Evap Purge Solenoid.

NOTE: After disconnecting the Evap Purge Solenoid vacuum connections, inspect the lines and solenoid for any signs of contamination from the EVAP Canister. This may indicate a faulty check valve. Replace/repair as necessary.

Using a hand vacuum pump, apply 10 in Hg to the "CAN" of the EVAP Purge Solenoid.

NOTE: Monitor the vacuum gauge for at least 15 seconds.

Does the EVAP Purge Solenoid hold vacuum?

Yes
1. Go To step 4).
No
1. Replace the Evap Purge Solenoid.
2. Perform POWERTRAIN VERIFICATION TEST .
4) NVLD SWITCH OPERATION
Ignition on, engine not running.

Using the scan tool, monitor the NVLD Switch State with the vacuum pump still installed and holding vacuum.

Does the scan tool display the NVLD state OPEN?

Yes
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 5).
  NOTE: Remove the vacuum pump and connect the vacuum hose before continuing.
5) NVLD ASSEMBLY
Disconnect the NVLD electrical connector.

Does the Switch change from CLOSED to OPEN?

Yes
1. Replace the NVLD Assembly.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 6).
6) (K107) SIGNAL CIRCUIT SHORTED TO GROUND

Fig 2: Checking NVLD Switch Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C3 PCM harness connector.

Measure the resistance between ground and the (K107) NVLD Switch Signal circuit in the NVLD Assembly harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (K107) NVLD Switch Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 8).
7) (K52) EVAP PURGE SOLENOID CONTROL CIRCUIT SHORTED TO GROUND

Fig 3: Checking EVAP Purge Solenoid Control Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C3 PCM harness connector.

Measure the resistance between ground and the (K52) Evap Purge Solenoid Control circuit in the EVAP Purge Solenoid harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (K52) Evap Purge Sol Control circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 8).
8) PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes
1. Repair as necessary.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Replace and program the Powertrain Control Module per Service Information.
2. Perform POWERTRAIN VERIFICATION TEST .