1999 Jeep Grand Cherokee Limited AUTOMATIC TRANSMISSIONS Chrysler 45RFE Electronic Controls Repair Manual

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INTERNAL TCM Circuit Description The TCM is reporting internal errors. Diagnostic Procedure 1. Turn ignition switch to LOCK position. Remove transmission control relay. Measure resistance between ground and relay ground circuit (Black/Yellow wire) in relay connector. If resistance is greater than 5 ohms, repair open circuit. If resistance s not greater than 5 ohms, go to next step. 2. The TCM has an internal problem and must be replaced. P0715: INPUT SPEED SENSOR ERROR Circuit Description DTC P0715 will set if an excessive change in input RPM has been detected in any gear. Possible Causes * Intermittent wiring and connector problems. * Faulty input speed sensor. * Input speed sensor circuits shorted to ground, shorted to voltage, or open. * Faulty TCM. Diagnostic Procedure 1. Place gear selector in “P” position and start engine. Using scan tool, monitor input speed sensor value. If value is less than 400 RPM, go to next step. If value is not less than 400 RPM, go to step 9. 2. Turn ignition switch to LOCK position. Install Transmission Simulator (8333). Turn ignition on. Using transmission simulator, turn rotary knob to middle (1000/3000) position. Turn INPUT/OUTPUT switch on. Using scan tool, monitor input and output speed sensor values. If input speed sensor value is 2950- 3050 RPM and output speed sensor value is 950-1050 RPM, replace input speed sensor. If speed sensor values are not as specified, go to next step. 3. Turn ignition switch to LOCK position. Disconnect TCM harness connector. Remove transmission control relay. Using fused jumper wire, jumper fused B+ circuit (Red/White wire) and transmission relay output circuit (Red wire) together at relay connector. Turn ignition on. Measure voltage between ground and input speed sensor signal circuit (Red/Black wire) at TCM harness connector. If voltage is greater than 3 volts, repair circuit for short to voltage. If voltage is not greater than 3 volts, remove jumper wire, install relay and go to next step. 4. Turn ignition switch to LOCK position. Disconnect input speed sensor harness connector. Measure resistance of input speed sensor signal circuit (Red/Black wire) between TCM and input speed sensor. If resistance is greater than 5 ohms, repair open circuit. If resistance is not greater than 5 ohms, go to next step. 5. Measure resistance of input speed sensor ground circuit (Dark Blue/Black wire) between TCM and input