Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
2009 Jeep Wrangler X, AutomaticSECTION Diagnostic Test
- CHECK FOR RELATED DTCS
- With the scan tool, read DTCs.
Are there any other line pressure DTCs present?
Yes
- See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Diagnosis and Testing and perform the appropriate diagnostic procedure. Perform the test for P0934 and/or P0935 first if present.
No
- Go to step 2
- With the scan tool, read DTCs.
- COMPARE ACTUAL LINE PRESSURE TO DESIRED LINE PRESSURE CAUTION: Apply Parking Brake
- Start the engine.CAUTION: Firmly apply the brakes.
- With the scan tool, monitor the Line Pressure, Desired Line Pressure and the TPS degrees.
- While firmly applying the brakes, place the shifter in reverse, then slowly press the accelerator pedal to a TPS degree of 15°.
- Compare the Line Pressure reading to the Desired Line Pressure reading on the scan tool.
Does the Line Pressure stay within ± 34 kPa or 5 psi of the Desired Line Pressure?
No
- Go to step 3
Yes
- Go to step 6
- Start the engine.
- CHECK LINE PRESSURE CONNECTOR AND WIRING
- Ignition on, engine not running.
- With the scan tool, monitor the Line Pressure Sensor voltage while wiggling the wiring harness and connectors pertaining to the Line Pressure Sensor and the Transmission Solenoid/TRS Assembly.
Did the voltage remain steady while wiggling the wiring harness and connectors?
Yes
- Go to step 4
No
- Disconnect and properly reconnect the Line Pressure Sensor connector. Inspect terminals and repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure .
- CHECK PCM AND WIRING
- Turn the ignition off to the lock position.
- Remove the Ignition Switch Feed fuse from the TIPM.CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being started in gear.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.