Engine Code

P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW






For a complete wiring diagram refer to: Electrical Diagrams

When Monitored
With the ignition on. Battery voltage greater than 10 volts.

Set Condition
Throttle Position Sensor voltage at the PCM is less than 0.16 of a volt for 0.7 of a second. One Trip Fault. Three good trips to turn off the MIL. ETC light will illuminate.

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 (K922) SENSOR RETURN CIRCUIT
- THROTTLE POSITION SENSOR/THROTTLE BODY
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test
1. ACTIVE DTC





NOTE: If a 5-Volt Supply DTC has also set, diagnose the 5-Volt DTC before continuing.

Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Yes >> Go To 2
No >> Go To 10

2. P0222 ALSO SET





Was the P0222-TP SENSOR NO.2 VOLTAGE LOW DTC set along with the P0122?
Yes >> Go To 3
No >> Go To 4

3. (F855) 5-VOLT SUPPLY CIRCUIT





Turn the ignition off.
Disconnect the Throttle Body harness connector.
Ignition on, engine not running.
Measure the voltage on the (F855) 5-volt Supply circuit in the Throttle Body harness connector.

Is the voltage between 4.8 to 5.2 volts?
Yes >> Go To 4
No >> Go To 7

4. THROTTLE POSITION SENSOR





With a scan tool, monitor the TP Sensor No.1 voltage with the Sensor harness connector disconnected.

Is the voltage above 4.5 volts?
Yes >> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Go To 5

5. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND





Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance between ground and the (K22) TP Sensor No.1 Signal circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?
Yes >> Repair the short to ground in the (K22) TP Sensor No.1 Signal circuit.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Go To 6

6. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K922) SENSOR RETURN CIRCUIT





Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (K922) Sensor Return circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?
Yes >> Repair the short between the (K922) Sensor Return circuit and the (K22) TP Sensor No.1 Signal circuit.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Go To 9

7. (F855) 5-VOLT SUPPLY CIRCUIT OPEN





Turn the ignition off.
Disconnect the PCM harness connectors.

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 diagnostics.

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 >> Go To 8
No >> Repair the open in the (F855) 5-volt Supply circuit.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





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

Is the resistance below 100 ohms?
Yes >> Repair the short to ground in the (F855) 5-volt Supply circuit.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Go To 9
9. 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 >> Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
10. THROTTLE FOLLOWER TEST





With a scan tool, perform the Throttle Follower Test.
Monitor the TP Sensor No.1 voltage.

Does voltage start at approximately 0.8 of a volt and go above 3.5 volts with a smooth transition?
Yes >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, using a scan tool select ETC RELEARN function.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test