What Does B1627 Mean?
This code indicates the Body Control Module (BCM) or Transmission Control Module (TCM) has detected a fault in the Reverse gear position input circuit of the PRNDL (Park-Reverse-Neutral-Drive-Low) switch or sensor. The module is not receiving the correct electrical signal when the transmission is shifted into Reverse position. This can affect reverse lights, backup cameras, parking assist systems, and potentially prevent the vehicle from starting or shifting properly.
Common Causes
45%
Faulty transmission range sensor (PRNDL switch) with failed reverse position contacts or worn internal components
30%
Damaged, corroded, or loose wiring harness connections at the transmission range sensor connector
15%
Broken or shorted wiring between the transmission range sensor and BCM/TCM
10%
Failed BCM or TCM with internal circuit fault in the PRNDL input processing
Diagnostic Steps
1
Step 1: Perform visual inspection of the transmission range sensor connector and wiring harness for corrosion, bent pins, moisture intrusion, or physical damage. Check connector locking tabs and ensure secure connection.
2
Step 2: Using a digital multimeter, backprobe the reverse position circuit at the transmission range sensor connector with the ignition on and shifter in Reverse. Compare voltage readings to manufacturer specifications (typically 5V reference, varying signal voltage, or ground depending on design).
3
Step 3: Check continuity of the reverse position signal wire from the transmission range sensor connector to the BCM/TCM connector using a wiring diagram. Test for shorts to ground or power, and verify ground circuit integrity with resistance measurement (should be less than 1 ohm).
4
Step 4: Monitor live data on the scan tool while cycling through all gear positions slowly. Observe if the reverse position is recognized by the control module or if the signal is intermittent or absent only in Reverse.
5
Step 5: If all wiring and connections test good, remove and inspect the transmission range sensor for physical damage, internal contact wear, or incorrect adjustment/alignment on the transmission shift linkage.
6
Step 6: After replacing the faulty component, clear codes, perform transmission range sensor relearn procedure if required, cycle through all gear positions, and verify reverse lights, backup camera, and all PRNDL-dependent systems function correctly.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) or Transmission Control Module (TCM) has detected a fault in the Reverse gear position input circuit of the PRNDL (Park-Reverse-Neutral-Drive-Low) switch or sensor. The module is not receiving the correct electrical signal when the transmission is sh...
The most common cause of B1627 (PRNDL Reverse Input Circuit Failure) is: Faulty transmission range sensor (PRNDL switch) with failed reverse position contacts or worn internal components
Typical repair costs for B1627 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive but reverse lights and backup camera may not function, creating a safety hazard when backing up. Some vehicles may experience no-start conditions or inability to shift out of Park until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1627 to identify the root cause.
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Quick Info
Category
Body
System
Transmission Control System / Body Electrical System
Difficulty
Type
Manufacturer
Recommended Tools
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