Window Position Sensor Feedback Loss
The B1236 code indicates that the Body Control Module (BCM) or Door Control Module (DDM/PDM) has detected a loss of feedback signal from the window motor position sensor. This sensor, which may be a Hall effect or potentiometer type, reports the exact glass position to the module for functions like auto up/down, pinch protection, and indexing. Without this signal, the module cannot control window movement safely or accurately.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty window motor position sensor (integrated into the motor)
- Open, short to ground, or short to battery in wiring between motor and control module (BCM/DDM)
- Loose, corroded, or damaged connector at the window motor
- Internal failure of the Door Control Module (DDM) or BCM
- Window mechanism binding or excessive mechanical resistance preventing expected movement
3. Symptoms You Will Notice
- Window does not operate or operates erratically
- Auto up/down function inoperative
- Pinch protection or indexing not working
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to window operation
Inspect window motor connector and wiring for damage, corrosion, or loose terminals
Test window motor position sensor signal using a scan tool or multimeter
Verify window regulator and track for binding or obstruction
If wiring and sensor are okay, test/replace the door control module or BCM
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive, but the affected window may not operate properly, which could be a security or convenience issue.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the issue is wiring, a window motor, or a control module.