What does it mean?
C1133 is a Chassis (ABS, traction control, steering) fault code. It indicates: Engine Signal 4 .
Symptoms
- Stability and traction warning lamps on, with those systems inactive
- Warning appears while driving and may clear on the next start
- Several modules record communication faults in the same session
- Some driver assistance functions become unavailable
- Engine performance may be reduced if the vehicle enters a protective mode
- Scan tool has trouble reaching one of the modules
Likely causes
- Intermittent open or high resistance in the network wiring between the modules
- Damaged CAN twisted pair, for example crushed during a previous repair
- Terminating resistance problem in the network causing message errors
- Water or corrosion in a connector on the network path
- Engine control module fault or a loss of its power supply while the ignition is on
- Weak system voltage causing one module to drop off the network briefly
- Faulty receiving module unable to process the incoming data
How to fix it
- Read codes from all modules and record which ones are missing from the network
- Check module power and ground before testing the bus itself
- Measure the resistance across the two CAN lines with the ignition off and compare with specification
- Inspect the harness for crushed, chafed or repaired sections along its route
- Wiggle test the connectors while monitoring live data for dropouts
- Repair the damaged network wiring or connector, then clear all modules and retest
- Consider module replacement and coding only after the network tests as good