B1627 – PRNDL Reverse Input Circuit Failure

The ODBII code B1627 PRNDL Reverse Input Circuit Failure indicates a malfunction in the circuit that detects the position of the transmission gear selector, specifically when the vehicle is in reverse.

The severity of ODBII code B1627 PRNDL Reverse Input Circuit Failure is generally considered moderate.

Common Causes For: B1626 Lamp Keypad Output Short Circuit To Ground

• Faulty PRNDL switch
• Wiring issues (shorts or open circuits)
• Poor connections or corroded terminals
• Malfunctioning transmission control module (TCM)
• Faulty vehicle speed sensor
• Issues with the engine control module (ECM)
• Grounding problems
• Damaged or frayed wiring harness

Common misdiagnosis for B1627 PRNDL Reverse Input Circuit Failure

• Transmission control module failure
• Faulty PRNDL switch
• Wiring issues or shorts in the harness
• Malfunctioning transmission range sensor
• Defective engine control module (ECM)
• Incorrectly calibrated transmission
• Faulty neutral safety switch
• Issues with the vehicle’s body control module (BCM)
• Problems with the gear selector assembly
• Software glitches in the vehicle’s computer systems

Common Troubleshooting Steps

The OBD-II code B1627 indicates a “PRNDL Reverse Input Circuit Failure.” This code is related to the transmission range sensor (also known as the PRNDL switch or transmission position sensor), which monitors the position of the gear selector in automatic transmissions. When this sensor fails or has a malfunction, it can trigger the B1627 code. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues present.
• Inspect the PRNDL Switch:
• Locate the PRNDL switch on the transmission.
• Check for any visible damage, corrosion, or loose connections.
• Ensure that the switch is properly aligned and securely mounted.
• Examine Wiring and Connectors:
• Inspect the wiring harness and connectors leading to the PRNDL switch for any signs of wear, fraying, or damage.
• Look for any loose or corroded connections that could affect the signal.
• Test the PRNDL Switch:
• Use a multimeter to test the PRNDL switch for proper operation. Check for continuity in the different positions (Park, Reverse, Neutral, Drive).
• Compare the readings to the specifications in the vehicle’s service manual.
• Check the Transmission Fluid Level:
• Low or contaminated transmission fluid can affect the operation of the transmission and its sensors. Ensure the fluid is at the correct level and in good condition.
• Inspect the Transmission Control Module (TCM):
• If the PRNDL switch and wiring are functioning correctly, the issue may lie with the TCM. Check for any software updates or known issues with the module.
• If necessary, perform a reset or reprogramming of the TCM.
• Look for Mechanical Issues:
• Ensure that the gear selector is functioning properly and is not binding or obstructed.
• Check for any mechanical issues within the transmission that could affect the PRNDL switch operation.
• Clear Codes and Test Drive:
• After performing repairs or adjustments, clear the trouble codes using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code reappears.
• Consult a Professional:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission systems and can perform more advanced diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1627 code.