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) THROTTLE POSITION SENSOR VOLTAGE BELOW 0.098 OF A VOLT
Ignition on, engine not running.

With a scan tool, read the TP Sensor voltage.

Is the voltage below 0.098 of a volt?

Yes
1. Go To step 2).
No
1. Go To step 9).
2) (F855) 5-VOLT SUPPLY CIRCUIT

Fig 1: Checking 5-Volt Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the TP Sensor harness connector.

Ignition on, engine not running.

Measure the voltage on the (F855) 5-volt Supply circuit in the TP Sensor harness connector.

Is the voltage between 4.5 to 5.2 volts?

Yes
1. Go To step 3).
No
1. Go To step 6).
3) THROTTLE POSITION SENSOR
With the a scan tool, monitor the TP Sensor voltage with the Sensor harness connector disconnected.

Is the voltage above 4.5 volts?

Yes
1. Replace the Throttle Position Sensor.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 4).
4) (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND

Fig 2: Checking Throttle Position Sensor No. 1 Signal Circuit Shorted to Ground
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Measure the resistance between ground and the (K22) TP Sensor No.1 Signal circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (K22) TP Sensor No.1 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 5).
5) (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Fig 3: Checking Throttle Position Sensor No. 1 Signal Circuit Shorted to Sensor Ground Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (K900) Sensor ground circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short between the (K900) Sensor ground and the (K22) TP Sensor No.1 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 8).
6) (F855) 5-VOLT SUPPLY CIRCUIT OPEN

Fig 4: Checking 5-Volt Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C2 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 (F855) 5-volt Supply circuit from the TP Sensor 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 (F855) 5-volt Supply circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
7) (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Fig 5: Checking 5-Volt Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between ground and the (F855) 5-volt Supply circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (F855) 5-volt Supply 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 .
9) THROTTLE POSITION SENSOR SWEEP
With a scan tool, monitor the Throttle Position Sensor voltage.

Slowly open the throttle from the idle position to the wide open throttle position.

Does voltage start at approximately 0.8 of a volt and go above 3.5 volts with a smooth transition?

Yes
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Replace the Throttle Position Sensor.
2. Perform POWERTRAIN VERIFICATION TEST .