(P0120) Electronic Throttle Control Motor Performance
(P0120) ELECTRONIC THROTTLE CONTROL MOTOR PERFORMANCE
When Monitored and Set Condition
^ When Monitored: Ignition on with no MAP Sensor DTCs set.
^ Set Condition: TP Sensor signals in the Throttle Body Assembly do not correlate to the MAP Sensor signal.
POSSIBLE CAUSES
TP SENSOR SWEEP
TP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
OPEN TP SIGNAL CIRCUIT
OPEN 5-VOLT SUPPLY CIRCUIT
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
OPEN SENSOR GROUND CIRCUIT
TP SENSOR #1 SIGNAL CIRCUIT SHORTED TO TP SENSOR #2 SIGNAL CIRCUIT
THROTTLE BODY ASSEMBLY
POWERTRAIN CONTROL MODULE
Diagnostic Test
1. CHECK FOR CURRENT DTC
Note: Diagnose any other Throttle Body Assembly DTC(s) before continuing.
Note: The throttle plate should be free from binding and carbon build up.
Note: Ensure the throttle plate is at the idle position.
Note: Inspect the engine for vacuum leaks.
Note: If the PCM detects and stores a DTC, the PCM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the DRB III at the same time the DTC is displayed.
Note: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for a DTC.
Turn the ignition on.
With the DRB III, erase PCM DTCs.
Note: It maybe necessary to road test the vehicle for this DTC to set. With the DRB III, read the PCM DTCs.
Did this DTC set again?
Yes>> Go To 2
No>> Go To 11
2. TP SENSOR
Turn the ignition off.
Connect the Throttle Body harness connector.
Turn the ignition on.
With the DRB III, monitor the TP Sensor #1 or #2 voltage.
Connect a jumper wire between the Sensor Ground circuit and the TP
Sensor #1 Signal circuit.
TP Sensor #1 voltage should change from approximately 4.5 volts to 0.5 of a volt?
For TP Sensor #2, connect a jumper wire between 5-volt supply circuit
and the TP Sensor #2 signal circuit.
TP Sensor #2 voltage should change from approximately 0 volts to 5.0 volts?
Note: Remove the jumper wire before continuing.
Is the voltage reading within the listed specifications?
Yes>> Replace the Throttle Body Assembly.
Perform Powertrain Verification Test - Ver 2
No>> Go To 3
3. TP SENSOR #1 AND #2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the PCM C3 harness connector.
Disconnect the Throttle Body Assembly harness connector.
Note: Check connectors-Clean/repair as necessary.
Turn the ignition on.
Measure the voltage on the TP #1 Signal and the TP #2 Signal circuits at the Throttle Body harness connector.
Is the voltage above 1.0 volts?
Yes>> Repair the short to voltage in the TP #1 or TP #2 Signal circuit.
Perform Powertrain Verification Test - Ver 2
No>> Go To 4
4. RESISTANCE IN THE #1 AND #2 TP SENSOR SIGNAL CIRCUITS
Turn the ignition off.
Measure the resistance of the TP Sensor #1 Signal circuit and TP Sensor
#2 Signal circuit from the Throttle Body harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 5
No>> Repair the excessive resistance in the or TP Sensor Signal circuit.
Perform Powertrain Verification Test - Ver 2
5. RESISTANCE BETWEEN GROUND AND THE TP SENSOR SIGNAL CIRCUIT
With the ignition off.
Measure the resistance between ground and the TP Sensor #1 Signal circuit and TP Sensor #2 Signal circuit at the Throttle Body harness connector.
Is the resistance below 100 ohms?
Yes>> Repair the short to ground in the Sensor #1 or Sensor #2 TP Sensor Signal circuit.
Perform Powertrain Verification Test - Ver 2
No>> Go To 6
6. RESISTANCE IN THE 5-VOLT SUPPLY CIRCUIT
With the ignition off.
Measure the resistance of the 5-Volt Supply circuit from the Throttle Body harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 7
No>> Repair the excessive resistance in the 5-Volt Supply circuit.
Perform Powertrain Verification Test - Ver 2
7. RESISTANCE TO GROUND IN THE 5-VOLT SUPPLY CIRCUIT
With the ignition off.
Measure the resistance between ground and the 5-Volt Supply circuit.
Is the resistance below 100 ohms?
Yes>> Repair the short to ground in the 5-Volt Supply circuit.
Perform Powertrain Verification Test - Ver 2
No>> Go To 8
8. OPEN SENSOR GROUND CIRCUIT
With the ignition off.
Measure the resistance of the Sensor Ground circuit from the Throttle
Body harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Yes>> Go To 9
No>> Repair the Sensor Ground circuit for an open.
Perform Powertrain Verification Test - Ver 2
9. TP SENSOR #1 SIGNAL CIRCUIT SHORTED TO TP SENSOR #2 SIGNAL CIRCUIT
With the ignition off.
Measure the resistance of the TP Sensor #1 Signal circuit and the TP Sensor #2 Signal circuit at the Throttle Body harness connector.
Is the resistance below 5.0 ohms?
Yes>> Repair the short between the TP Sensor #2 Signal circuit and the TP Sensor #1 Signal circuit.
Perform Powertrain Verification Test - Ver 2
No>> Go To 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.
If there are no possible causes remaining, review repair.
Repair>> Replace and program the Powertrain Control Module.
Perform Powertrain Verification Test - Ver 2
11. TP SENSOR SWEEP
With the ignition on.
With the DRB III, monitor the APPS TP Sensor #1 or #2 voltage.
Slowly depress the Pedal from the idle position to the wide open throttle position.
The voltage for TP Sensor #1 should start at approximately 0.8 of a volt and increase to above 4.2 volts.
The voltage for TP Sensor #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 TP Sensor?
Yes>> Go to 12
No>> Replace the Throttle Body Assembly.
Perform Powertrain Verification Test - Ver 2
12. INTERMITTENT WIRING AND CONNECTORS
The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.
Note: Check connectors-Clean/repair as necessary. Poor pin to terminal connections can set DTCs.
Note: Check for any Technical Service Bulletins that may apply.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors specific to this DTC. Wiggle the wires while checking for shorts and open circuits.
Were there any problems found?
Yes>> Repair as necessary.
Perform Powertrain Verification Test - Ver 2
No>> The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.
(P0120) THROTTLE POSITION SENSOR 1/2 CORRELATION
When Monitored and Set Condition
^ When Monitored: Ignition on with no MAP Sensor DTCs set.
^ Set Condition: TP Sensor signals in the Throttle Body Assembly do not correlate to the MAP Sensor signal.
POSSIBLE CAUSES
THROTTLE POSITION SENSOR SWEEP
THROTTLE POSITION SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
THROTTLE POSITION SENSOR SIGNAL CIRCUIT OPEN
THROTTLE POSITION SENSOR GROUND CIRCUIT OPEN
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5-VOLT SUPPLY CIRCUIT OPEN
THROTTLE POSITION SENSOR #1 SIGNAL CIRCUIT SHORTED TO THROTTLE POSITION SENSOR #2
SIGNAL CIRCUIT
THROTTLE BODY ASSEMBLY
POWERTRAIN CONTROL MODULE
Diagnostics Test
1. CHECK FOR CURRENT DTC
Turn the ignition on.
With the DRB III, read the PCM DTCs.
Is this DTC present?
Yes>> For complete diagnosis of this DTC, refer to (P0120) ELECTRONIC THROTTLE CONTROL MOTOR PERFORMANCE.
No>> Go To 2
2. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Note: Check connectors-Clean/repair as necessary. Poor pin to terminal connections can set DTCs. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors specific to this DTC. Wiggle the wires while checking for shorts and open circuits.
Note: Check for any Technical Service Bulletins that may apply.
Were there any problems found?
Yes>> Repair as necessary.
Perform Powertrain Verification Test - Ver 2
No>> The condition that caused this DTC to set is currently
not present. Inspect the related wiring harness for a possible intermittent condition.