What does it mean?
C1096 is a Chassis (ABS, traction control, steering) fault code. It indicates: ABS Hydraulic Pump Motor Circuit Open . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- ABS warning lamp on shortly after every start
- The usual pump buzz during the start up self test is missing
- Pedal drops further than normal during an ABS event because pressure is not restored
- Stability and traction control switched off with the ABS
- Wheel lock up and longer stopping distances on loose or wet surfaces
- Code returns immediately after clearing
Likely causes
- Blown high current fuse or fusible link feeding the pump motor
- Broken, corroded or backed out terminal in the pump motor connector
- Open in the ground path of the hydraulic unit, including a loose or rusty ground bolt
- Pump relay not closing because of a burnt contact or an open coil
- Worn brushes or an open winding inside the pump motor after long inactivity
- Harness damaged by rodents, road debris or a previous repair near the modulator
- Open output driver inside the ABS control module
How to fix it
- Check the ABS high current fuse and the fusible link with a meter, not just by eye
- Back probe the pump motor connector and look for battery voltage on the feed with the pump commanded
- Measure resistance across the pump motor terminals with the connector unplugged
- Clean and tighten the hydraulic unit ground point and check the strap for corrosion
- Test the pump relay by swapping it with an identical relay or by bench testing it
- Repair the open circuit in the harness, then confirm the pump runs on scan tool command
- Replace the pump motor or hydraulic unit only when the wiring, fuse and relay test good