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
NOTE: The throttle plate and linkage should be free from binding and carbon build up.

NOTE: Make sure the throttle plate is at the idle position.

Ignition on, engine not running.

NOTE: Inspect the engine for vacuum leaks.

With a scan tool, read DTCs.

Is the DTC active at this time?

Yes
1. Go To step 2).
No
1. Go To step 11).
2) (K22) TP SENSOR NO.1 OR (K122) TP SENSOR NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

Fig 1: Checking Throttle Position Sensor No. 1 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Fig 2: Checking Throttle Position Sensor No. 2 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Disconnect the Throttle Body harness connector.

Ignition on, engine not running.

Measure the voltage on the (K22) TP No.1 Signal and the (K122) TP No.2 Signal circuits in the Throttle Body harness connector.

Is the voltage above 0 volts?

Yes
1. Repair the short to battery voltage in the (K22) TP Sensor No.1 or (K122) TP Sensor No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 3).
3) THROTTLE POSITION SENSOR

Fig 3: Checking Throttle Position Sensor No. 1 Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Fig 4: Checking Throttle Position Sensor No. 2 Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Connect the C2 PCM harness connector.

Ignition on, engine not running.

With a scan tool, monitor the TP Sensor No.1 and No.2 voltage.

Connect a jumper wire between the (K922) Sensor Return circuit and the (K22) TP Sensor No.1 Signal circuit.

TP Sensor No.1 voltage should change from approximately 4.5 volts to 0.5 of a volt?

For TP Sensor No.2, connect a jumper wire between (F855) 5-volt supply circuit and the (K122) TP Sensor No.2 signal circuit.

TP Sensor No.2 voltage should change from approximately 0 volts to 5.0 volts?

Is the voltage reading within the listed specification with the jumper wire installed?

Yes
1. Replace the Throttle Body Assembly.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 4).
NOTE: Remove the jumper wire before continuing.
4) EXCESSIVE RESISTANCE IN THE (K22) TP SENSOR NO.1 OR (K122) TP SENSOR NO.2 SIGNAL CIRCUIT

Fig 5: Checking Throttle Position Sensor No. 1 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Fig 6: Checking Throttle Position Sensor No. 2 Signal 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 (K22) TP Sensor No.1 Signal circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Measure the resistance of the (K122) TP Sensor No.2 Signal circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms for each circuit?

Yes
1. Go To step 5).
No
1. Repair the excessive resistance in the (K22) TP Sensor No.1 or (K122) TP Sensor No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
5) (K22) TP SENSOR NO.1 OR (K122) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND

Fig 7: Checking Throttle Position Sensor No. 1 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Fig 8: Checking Throttle Position Sensor No. 2 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between ground and the (K22) TP Sensor No.1 Signal circuit and the (K122) TP Sensor No.2 Signal circuit at the appropriate terminals of special tool #8815.

Is the resistance below 100 ohms for each circuit?

Yes
1. Repair the short to ground in the (K22) TP No.1 Signal or (K122) TP No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 6).
6) EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT

Fig 9: Checking 5-Volt Supply Circuit
Courtesy of DAIMLERCHRYSLER CORP.

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 Throttle Body 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 excessive resistance in the (F855) 5-volt Supply circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
7) (F855) 5-VOLT SUPPLY SHORTED TO GROUND

Fig 10: Checking 5-Volt Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between ground and the (F855) 5-volt Supply circuit at the appropriate terminals of special tool #8815.

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) EXCESSIVE RESISTANCE IN THE (K922) SENSOR RETURN CIRCUIT

Fig 11: Checking Throttle Position Sensor Return Circuit
Courtesy of DAIMLERCHRYSLER CORP.

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 (K922) Sensor Return circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 9).
No
1. Repair the excessive resistance in the (K922) Sensor Return circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
9) (K22) TP SENSOR NO.1 SIGNAL SHORTED TO (K122) TP SENSOR NO.2 SIGNAL

Fig 12: Checking Throttle Position Sensor Signal Circuits
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (K122) TP Sensor No.2 Signal circuit between the appropriate terminals of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Repair the short between the (K122) TP Sensor No.2 Signal circuit and the (K22) TP Sensor No.1 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 10).
10) 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.

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 .
11) THROTTLE FOLLOWER TEST
Ignition on, engine not running.

With a scan tool, perform the Throttle Follower Test and monitor the TP Sensor No.1 or No.2 voltage.

Slowly press the throttle pedal down.

The voltage for TP Sensor No.1 should start at approximately 0.8 of a volt and increase to above 4.2 volts.

The voltage for TP Sensor No.2 should start at approximately 4.2 volts and decrease to approximately 0.8 of a volt.

Is the voltage within the range of the listed specification for the appropriate Sensor?

Yes
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
2. Perform POWERTRAIN VERIFICATION TEST .