P0122

DTC P0122: Low Voltage in TP Sensor Circuit
1. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, then turn the ignition switch OFF.
2. Turn the ignition switch ON(II).
3. Check the throttle position with the scan tool.
Is there approx. 10% when the throttle is fully closed and approx. 90% when the throttle is fully opened?
YES-Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the TP sensor and the ECM/PCM.
NO-Go to step 4.
4. Turn the ignition switch OFF.
5. Disconnect the TP sensor connector.
6. Turn the ignition switch ON (II).




7. Measure voltage between the TP sensor 3P connector terminals No.1 and No.3.
Is there approx. 5 V?
YES-Go to step 8.
NO-Go to step 14.
8. Turn the ignition switch OFF.




9. At the sensor side, measure resistance between the TP sensor 3P connector terminals No.1 and No.2 with the throttle fully closed.
Is there approx. 0.5-0.9 kOhm?
YES-Go to step 10.
NO-Replace the throttle body.




10. Measure resistance between the TP sensor 3P connector terminals No.2 and No.3 with the throttle fully closed.
Is there approx. 4.5 kOhm?
YES-Go to step 11.
NO-Replace the throttle body.
11. Reconnect the TP sensor connector.

12. Turn the ignition switch ON (II).




13. Measure voltage between ECM/PCM connector terminals C18 and C27.
Is there approx. 0.5 V when the throttle is fully closed and approx. 4.5 V when the throttle is fully opened?
YES-Substitute a known-good ECM/PCM and recheck. If prescribed voltage is now available, replace the original TP sensor.
Diagnostic Strategies

NO-Repair short in the wire between the ECM/PCM (C27) and the TP sensor.




14. Measure voltage between ECM/PCM connector terminals C18 and C28.
Is there approx. 5 V?
YES-Repair open in the wire between the ECM/PCM (C28) and the TP sensor.
NO-Substitute a known-good ECM/PCM and recheck . If prescribed voltage is now available, replace the original ECM/PCM.
Diagnostic Strategies