DTC P0121: Throttle Position (TP) CKT Range/Performance Problem
NOTE:
If DTC P1450 or P1451 is set, diagnose them first.
- Turn ignition on. Using a voltmeter, backprobe PCM 16-pin harness connector. DO NOT
disconnect connector. Measure voltage between ground and terminal No. 6 (Light Green/White wire) with throttle closed (idle position) and fully open (WOT). As throttle position is changed from closed to open, TP sensor voltage should rise steadily. See TP SENSOR VOLTAGE
table. If TP sensor tests as specified, inspect PCM harness connector. If connector is okay, replace PCM. If TP sensor voltage is not as specified, go to next step.TP SENSOR VOLTAGE
Throttle Position Volts Closed 0.1-1.1 Open 2.8-4.8 - Turn ignition off. Disconnect TP sensor harness connector. Using an ohmmeter, measure resistance between specified TP sensor terminals. See Fig 1 . See TP SENSOR RESISTANCE table. Replace TP sensor if resistance is not as specified. If resistance is as specified, check Light Green wire, Light Green/White wire or Light Green/Black wire between TP sensor and PCM for continuity. Repair as necessary. If wires are okay, replace PCM. Retest system.
TP SENSOR RESISTANCE
| Between Terminals No. | Ohms | ||
|---|---|---|---|
| 1 & 2 | 2500-6000 | ||
| 1 & 3 | (1) 100-20,000 | ||
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