Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U1040: Lost Communications With Electronic Brake/Traction Control Module (EBTCM)
2000 Saturn SL2 Automatic, MP6SECTION DTC U1040: Lost Communications With Electronic Brake/Traction Control Module (EBTCM)
- Perform VEHICLE ON-BOARD DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If body control module diagnostic system check has been performed, go to next step.
- Observe scan tool display for DTC U1040. If scan tool displays LAST TEST FAILED for DTC U1040, go to next step. If scan tool does not display LAST TEST FAILED for DTC U1040, problem is intermittent. Check for poor connection at Electronic Brake/Traction Control Module (EBTCM). Check for open or poor connection in serial data line (Purple wire). See ANTI-LOCK BRAKES article in WIRING DIAGRAMS. Repair as necessary and retest operation.
- Turn ignition off. Gain access to Electronic Brake/Traction Control Module (EBTCM) located in left rear corner of engine compartment. Disconnect EBTCM. Connect test light between ground and Black 30-pin EBTCM connector terminal No. 13 (Red wire). See Fig 1. See ANTI-LOCK BRAKES article in WIRING DIAGRAMS. If test light illuminates, go to step 5. If test light does not illuminate, go to next step.
- Repair open in Red wire between Black 30-pin EBTCM connector terminal No. 13 and ABS fuse (50-amp), located in underhood fuse block. See COMPONENT LOCATIONS . Retest operation.
- Connect test light between ground and Black 30-pin EBTCM connector terminal No. 30 (Brown wire). Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, repair open in Brown wire between Black 30-pin EBTCM connector terminal No. 30 and IGN 3 fuse (10-amp), located in instrument panel fuse block. Retest operation.
- Connect test light between battery voltage and Black 30-pin EBTCM connector terminals No. 12 and 15 (Black wires). If test light illuminates, go to next step. If test light does not illuminate, repair open in appropriate Black wire between EBTCM and ground. See GROUND DISTRIBUTION article in WIRING DIAGRAMS.
- Check for poor connections to EBTCM. Repair as necessary. If EBTCM connections are okay, replace EBTCM. See appropriate ANTI-LOCK article in BRAKES.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.