Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see CHEROKEE wiring diagram in WIRING DIAGRAMS article.
Note. DTC P0122: THROTTLE POSITION SENSOR VOLTAGE LOW is monitored with ignition on and battery voltage more than 10.4 volts. DTC may be stored in Powertrain Control Module (PCM) when PCM senses Throttle Position (TP) sensor voltage is .1 volt for 3.2 seconds. Possible causes are: defective TP sensor, defective PCM, defective connectors or defective wiring.
- Turn ignition on, with engine off. Using scan tool, read TP sensor voltage. If voltage is less than .2 volt, go to next step. If voltage is .2 volt or more, go to step 8).
- Ensure ignition is off. Disconnect TP sensor connector. Clean and/or repair connector as necessary. Turn ignition on, with engine off. Using a voltmeter, check voltage on TP sensor connector, 5-volt supply circuit (Orange wire). If voltage is less than 4 volts, repair open 5-volt supply circuit. Perform TEST VER-5A. If voltage is 4 volts or more, go to next step.
- Turn ignition off. Ensure TP sensor connector is still disconnected. Turn ignition on with engine off. Using scan tool, read TP sensor voltage. If voltage is more than one volt, replace TP sensor. Perform TEST VER-5A. If voltage is one volt or less, go to next step.
- Turn ignition off. Ensure TP sensor connector is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. Clean and/or repair connectors as necessary. Using an ohmmeter, check resistance between ground and TP sensor connector, signal circuit (Orange/Dark Blue wire). If resistance is less than 5 ohms, repair signal circuit for short to ground. Perform TEST VER-5A. If resistance is 5 ohms or more, go to next step.
- Ensure ignition is off. Ensure TP sensor and PCM connectors are still disconnected. Using ohmmeter, check resistance between TP sensor connector, sensor ground circuit (Brown/Yellow wire) and signal circuit (Orange/Dark Blue wire). If resistance is less than 5 ohms, repair sensor ground circuit for short to signal circuit. Perform TEST VER-5A. If resistance is 5 ohms or more, go to next step.
- Turn ignition off. Disconnect Transmission Control Module (TCM) connector. TCM is located above accelerator pedal. Clean and/or repair connector as necessary. Turn ignition on with engine off. Using scan tool, read TP sensor voltage. If voltage is more than one volt, replace TCM. Perform TEST VER-5A. If voltage is one volt or less, go to next step.
- At this time, PCM is assumed to be defective. Replace PCM. Perform TEST VER-5A.
- Start engine and allow it to idle. Wiggle TP sensor connector and wiring harness while monitoring engine RPM. If an RPM change occurs while wiggling connector and wiring harness, repair connector or wiring harness where wiggling caused RPM to change. Perform TEST VER-5A. If no RPM change occurs, go to next step. NOTE: Throttle linkage must be moved very slowly while looking for a smooth change in voltage in this step.
- Turn engine off. Turn ignition on, with engine off. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage change is smooth, go to next step. If voltage change is erratic, replace TP sensor. Perform TEST VER-5A.
- Turn ignition on, with engine off. Wiggle TP sensor connector and wiring harness while monitoring TP sensor voltage. If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. Perform TEST VER-5A. If voltage does not change, go to next step.
- Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If connectors and wiring harness are okay, test is complete.