Pinpoint Test D - MLP Sensor
NOTE:
Code 634 may be set if transaxle is not in park or A/C is on when QUICK TEST is performed.
- Preliminary Inspection
Disconnect MLP connector, and inspect it for damaged pins, corrosion and loose wires. Repair as necessary. Reconnect MLP connector. Ensure MLP sensor is correctly adjusted. Refer to the appropriate AUTO TRANS DIAGNOSIS - AXOD-E article. If sensor requires adjustment, clear trouble codes after adjustment. See CLEARING CODES . Repeat QUICK TEST . If sensor is correctly adjusted, go to next step. - Check Electrical Signal Operation
Ensure ignition is off. Disconnect MLP harness connector. Turn ignition on. Measure voltage between harness connector TOT terminal and SRTN terminal. See Figure. If voltage is 4.75-5.25 volts, go to next step. If voltage is not within specification, Refer to the TESTS W/CODES - EEC-IV article in the ENGINE PERFORMANCE section for NO VREF voltage. - Check Continuity Of MLP Sensor Harness Circuits
Turn ignition off. Disconnect PCM 60-pin connector, and inspect it for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure and record resistance between Breakout Box test pin terminal No. 46 and MLP harness connector terminal No. 359. See Fig 1. Measure and record resistance between Breakout Box test pin terminal No. 30 and MLP harness connector terminal No. 199. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open circuit(s). Remove Breakout Box and connect all components. Erase all trouble codes. See CLEARING CODES . Repeat QUICK TEST . - Check MLP Circuit For Shorts To Power & Ground
Ensure MLP sensor harness connector is disconnected. Measure resistance between Breakout Box test pin No. 30 and test pins No. 37, 40, 46, 57 and 60. Measure resistance between Breakout Box test pin No. 30 and ground. If each measurement is more than 10 k/ohms, go to next step. If any measurement is less than 10 k/ohms, repair short circuit. Remove Breakout Box and connect all components. Erase all trouble codes. See CLEARING CODES . Repeat QUICK TEST . - Operational Check of MLP Sensor
Install MLP overlay on Transmission Tester (007-0085A). Connect tester to MLP sensor. Check continuity and resistances in all positions. See Fig 2. If MLP sensor does not operate within specification, replace sensor. Connect all components. Erase all trouble codes. See CLEARING CODES . Repeat QUICK TEST . If sensor operates within specification, connect all components. Erase all trouble codes. See CLEARING CODES. Repeat QUICK TEST . If code(s) 522, 634 or 659 are set, intermittent condition may be present. Attempt to duplicate malfunction by repeating previous steps.