Possible causes
– Faulty Left Rear ABS Sensor
– Left Rear ABS Sensor harness is open or shorted
– Left Rear ABS Sensor circuit poor electrical connection
– Faulty Wheel Speed Sensor
– Wheel bearing
– Left Rear ABS Sensor harness is open or shorted
– Left Rear ABS Sensor circuit poor electrical connection
– Faulty Wheel Speed Sensor
– Wheel bearing
Tech notes
There is factory service bulletin for the following Mercury models:
2002 Mercury Mountaineer
2003 Mercury Mountaineer
2004 Mercury Mountaineer
Mercury Mountaineer Factory Service Bulletin OBDII Code C1236
Symptoms
– ABS light ON
MERCURY Technical Service Bulletins for C1236 code
2005 MERCURY MONTEREY SERVICE BRAKES, HYDRAULIC:ANTILOCK:ABS WARNING LIGHT
2002 MERCURY MOUNTAINEER SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT
2003 MERCURY MOUNTAINEER SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT
2004 MERCURY MOUNTAINEER SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT
2002 MERCURY MOUNTAINEER SERVICE BRAKES, HYDRAULIC:ANTILOCK:CONTROL UNIT/MODULE
2003 MERCURY MOUNTAINEER SERVICE BRAKES, HYDRAULIC:ANTILOCK:CONTROL UNIT/MODULE
2004 MERCURY MOUNTAINEER SERVICE BRAKES, HYDRAULIC:ANTILOCK:CONTROL UNIT/MODULE
2002 MERCURY MOUNTAINEER SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT
2003 MERCURY MOUNTAINEER SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT