Jeep Fault Code
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High idle; Transmission shifting issues (XJ Auto); Engine won't return to idle quickly.
System
Not specified
Symptom
High idle; Transmission shifting issues (XJ Auto); Engine won't return to idle quickly.
Diagnosis & fix steps
Throttle Position Sensor (TPS) Voltage High/Low.
LOGIC: The TPS signal is out of range or has "dead spots" in the internal resistor.
ACTION: 1. Test the sensor with an analog voltmeter; look for a smooth needle sweep as you open the throttle.
2. Check for 5V reference.
FIX: Replace the Throttle Position Sensor.
Red Seal field insights
Never "wash" a Jeep 4.0L engine with a pressure washer. Water gets into the TPS very easily and causes a "high idle" or erratic shifting in the AW4 automatic transmission.
Same code keeps coming back?
That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.
Read before you touch anything
- This is general reference information, not a repair manual. It is for trained, qualified technicians.
- Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
- Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
- You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
- Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.
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