What does it mean?
C1700 is a Chassis (ABS, traction control, steering) fault code. It indicates: HECU Pin Coding Fault .
Symptoms
- ABS, stability and brake warning lamps on, usually immediately after a repair or module replacement
- ABS, traction and stability control fully disabled; plain hydraulic braking remains
- The code cannot be cleared and returns instantly
- Some live data is missing or shows default values
- Vehicle otherwise drives normally with no unusual noise
Likely causes
- Control unit fitted without being coded or configured for this vehicle
- Used or incorrect HECU installed that is coded for a different variant or brake system
- Coding pin circuit in the vehicle harness open, shorted or wired to the wrong ground
- Bent, backed out or corroded terminals in the HECU connector
- Harness repair or connector replacement that changed the coding pin arrangement
- Software update or programming interrupted, leaving an invalid configuration
- Internal fault in the control unit's coding input circuit
How to fix it
- Compare the part number and variant of the fitted HECU with the vehicle specification
- Check whether the unit was recently replaced, repaired or reprogrammed
- Inspect the HECU connector for bent, corroded or backed out terminals and for repair splices
- Test the coding pin circuits for the expected open or ground condition according to the vehicle data
- Carry out the module coding and configuration procedure with a capable scan tool
- Program the correct software level and variant, then clear the codes and run a self test
- Fit a correctly coded unit if a used or mismatched control unit cannot be configured