LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 82 (Automatic Transmission Diagnosis - ALLISON) >> Diagnostic Tests >> DTC P0875/P1713: Reverse Pressure Switch Circuit Malfunction >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the diagnostic system check? If so, go to next step. If not, see DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Check the transmission fluid level. See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Is the transmission fluid level correct? If so, go to next step. If not, see appropriate AUTOMATIC article in TRANSMISSION SERVICING.
  3. Measure the line pressure. See HYDRAULIC PRESSURE TESTS  under PERFORMANCE TESTS. Is the pressure within the specified value? If so, go to next step. If not, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
  4. This DTC is set when Park, Neutral, or a forward gear range is selected, and the Reverse pressure switch indicates mechanically closed or electrically on for a period of time that is calibration dependent. This DTC may indicate that a short circuit condition exists in the vehicle harness, internal transmission harness, or the pressure switch manifold. A defective PNP switch may set this DTC. The intent of this DTC is to detect discrepancies between range selected at the PNP and the actual position of the manual selector valve. Go to next step.
  5. Turn ignition off. Remove the C2 connector from the TCM, and connect the Breakout Box (J-39700) and Breakout Box Adapter (J-43799) to the TCM. Do not connect the vehicle harness to the breakout box adapter. Connect TCM connector C2 terminal No. 4 on the breakout box to a known-good chassis ground. Turn ignition on. Does the scan tool indicate Reverse pressure switch status as ON when grounded and OFF when open? If so, go to next step. If not, go to step  13.
  6. Turn ignition off and reconnect the C2 connector to the TCM. Disconnect the transmission in-line 20-way harness connector. Connect a wire between engine side of transmission in-line 20-way harness connector terminal "K" to a known-good ground. Turn ignition on. Does the scan tool indicate Reverse pressure switch status as ON when grounded and OFF when open? If so, go to next step. If not, go to step  12.
  7. Remove the oil pan. See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Disconnect the internal wiring harness from the pressure switch manifold, and ground pressure switch manifold connector terminal "D" to a known-good ground. Does the scan tool indicate Reverse pressure switch status as ON when grounded and OFF when open? If so, go to next step. If not, go to step  11.
  8. Remove the pressure switch manifold from the control valve body and leave the internal harness connected. Provide a ground connection from the pressure switch manifold frame to either the control valve body or the transmission main case. Use your finger to push gently on the Reverse pressure switch membrane (1). See Figure. Does the scan tool indicate Reverse pressure switch cycles from ON to OFF? If so, go to step  10. If not, go to next step.
  9. Replace the pressure switch manifold. See PRESSURE SWITCH MANIFOLD  under REMOVAL & INSTALLATION. Is the replacement complete? If so, go to step  14.
  10. Inspect for a missing or damaged seal at the switch assembly. Inspect for a loose Reverse transfer tube. Check the shift linkage adjustment. An out-of-adjustment linkage can cause a pressure switch malfunction. See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Was a problem found and corrected? If so, go to step  14. If not, see DIAGNOSTIC AIDS .
  11. Replace the internal wiring harness. See TRANSMISSION INTERNAL WIRING HARNESS  under REMOVAL & INSTALLATION. Is the replacement complete? If so, go to step  14.
  12. Repair the vehicle wiring harness. Is the repair complete? If so, go to step  14.
    13. CAUTION: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM.
  13. Replace the TCM. See TRANSMISSION CONTROL MODULE  under REMOVAL & INSTALLATION. Is the replacement complete? If so, go to next step.
  14. Perform the following procedure to verify the repair:
    • Clear the DTC.
    • Operate the vehicle under normal driving conditions.
    • Using the scan tool, monitor Reverse pressure switch operation.

    Did the DTC return? If so, go to step  1. If not, system is okay.

scientia non olet · About LEMON Manuals