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) (A15) ASD RELAY OUTPUT CIRCUIT

Fig 1: Checking ASD Relay Output at Ignition Coil No. 8
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Coil on Plug harness connector.

Ignition on, engine not running.

With a scan tool, actuate the ASD Relay.

Using a 12-volt test light connected to ground, probe the (A15) ASD Relay Output circuit in the Coil on Plug harness connector.

Does the test light illuminate brightly?

Yes
1. Go To step 3).
No
1. Repair the open or short to ground in the (A15) ASD Relay Output circuit between the IPM and Coil harness connector.
2. Perform POWERTRAIN VERIFICATION TEST .
NOTE: Stop All Actuations.
3) COIL ON PLUG RESISTANCE
Turn the ignition off.

NOTE: The following resistance measurement should be taken at 70°-80° F.

Measure the resistance of the Coil on Plug.

4.7L Primary Ignition Coil resistance is 0.6 to 0.9 of an ohm at 77°F (25°C).

5.7L Primary Ignition Coil resistance is 0.558 to 0.682 of an ohm at 77°F (25°C).

Is the resistance within the given specification for the Ignition Coil being tested?

Yes
1. Go To step 4).
No
1. Replace the Coil on plug.
2. Perform POWERTRAIN VERIFICATION TEST .
4) IGNITION COIL

Fig 2: Checking Ignition Coil
Courtesy of DAIMLERCHRYSLER CORP.

Using a 12-volt test light connected to a 12-volt source, probe the (K98) Coil Control No.8 circuit.

Crank the engine for 5 seconds while observing the test light.

What is the state of the test light while cranking the engine?

Brightly blinking.
1. Replace the Coil on plug.
2. Perform POWERTRAIN VERIFICATION TEST .
ON constantly.
1. Go To step 5).
OFF constantly.
1. Go To step 6).
5) (K98) COIL CONTROL NO.8 CIRCUIT SHORTED TO GROUND

Fig 3: Checking Coil Control No. 8 Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C1 PCM harness connector.

Measure the resistance between ground and the (K98) Coil Control No.8 circuit in the Coil on Plug harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (K98) Coil Control No.8 circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 7).
6) (K98) COIL CONTROL NO.8 CIRCUIT OPEN

Fig 4: Checking Coil Control No. 8 Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C1 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K98) Coil Control No.8 circuit from the Coil on Plug harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 7).
No
1. Repair the open in the (K98) Coil Control No.8 circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
7) 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 .