Page 977 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
Throttle Position Sensor voltage at the PCM is less than 0.1 of a volt for 1.3seconds.
Possible Causes
(F855) 5-VOLT SUPPLY CIRCUIT OPEN
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
(K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
(K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
THROTTLE POSITION SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
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 0.2 of a volt?
Ye s>>
Go To 2
No>>
Go To 9
2.(F855) 5-VOLT SUPPLY CIRCUIT
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 Sen-
sor harness connector.
Is the voltage between 4.5 to 5.2 volts?
Ye s>>
Go To 3
No>>
Go To 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?
Ye s>>
ReplacetheThrottlePositionSensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
Page 978 of 5267
4.(K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Measure the resistance between ground and the (K22) TP Sensor Sig-
nal circuit in the TP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K22) TP Sensor Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.(K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K22) TP Sensor Signal circuit and
the (K900) Sensor ground circuit in the TP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (K900) Sensor ground and the
(K22) TP Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
Page 979 of 5267

6.(F855) 5-VOLT SUPPLY CIRCUIT OPEN
Turn the ignition off.
Disconnect the PCM harness connector.
Measure the resistance of the (F855) 5-volt Supply circuit from the TP
Sensor harness connector to the appropriate terminal of the PCM.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (F855) 5-volt Supply circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
7.(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F855) 5-volt Supply
circuit in the TP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (F855) 5-volt Supply cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 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?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 980 of 5267
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 witha smooth transition?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
ReplacetheThrottlePositionSensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 981 of 5267
P0123-THROTTLE POSITION SENSOR #1 VOLTAGE TOO HIGH
For a complete wiring diagramRefer to Section 8W.
Page 982 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
Throttle Position Sensor voltage at the PCM is greater than 4.50 volts for 3.2 seconds.
Possible Causes
(K22) TP SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K22) TP SENSOR SIGNAL CIRCUIT OPEN
(K22) TP SENSOR SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
(K900) SENSOR GROUND CIRCUIT OPEN
THROTTLE POSITION SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.TP SENSOR VOLTAGE ABOVE 4.5 VOLTS
NOTE: Make sure the throttle is fully closed and free from binding or carbonbuild up.
Start the engine.
With a scan tool, read the TP Sensor voltage.
Is the voltage above 4.5 volts?
Ye s>>
Go To 2
No>>
Go To 8
2.THROTTLE POSITION SENSOR
Turn the ignition off.
Disconnect the TP Sensor harness connector.
Connect a jumper wire between the (K22) TP Sensor Signal circuit and
the (K900) Sensor ground circuit in the Sensor harness connector.
With a scan tool, monitor the TP Sensor voltage.
Ignition on, engine not running.
Is the voltage below 0.5 of a volt with the jumper wire
installed?
Ye s>>
ReplacetheThrottlePositionSensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
NOTE: Remove the jumper wire before continuing.
Page 983 of 5267
3.(K22) TP SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (K22) TP Sensor Signal circuit in the TP
Sensor harness connector.
Is the voltage above 0 volts?
Ye s>>
Repair the short to battery voltage in the (K22) TP Sensor
Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K22) TP SENSOR NO.1 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (K22) TP Sensor Signal circuit from the
TP Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the open in the (K22) TP Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 984 of 5267

5.(K22) TP SENSOR SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
Measure the resistance between the (K22) TP Sensor Signal circuit and
the (F855) 5-volt Supply circuit in the TP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (F855) 5-volt Supply circuit
and the (K22) TP Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the TP
Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)