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.
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HOMESERVICE MANUALSSATURN2000LW1 AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTBODY INTERIORBODY CONTROL MODULESDIAGNOSTIC TESTSDTC U1064: LOST COMMUNICATIONS WITH BCM
2000 Saturn LW1 Automatic
DTC U1064: Lost Communications With BCM
2000 Saturn LW1 AutomaticSECTION DTC U1064: Lost Communications With BCM
- Perform VEHICLE ON-BOARD DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If vehicle on-board diagnostic system check has been performed, go to next step.
- Turn ignition on. Using scan tool, observe scan tool display for DTC U1064. If scan tool displays LAST TEST FAILED for DTC U1064, go to next step. If scan tool does not display LAST TEST FAILED for DTC U1064, problem is intermittent. Check for poor connections to BCM. See COMPONENT LOCATIONS and WIRING DIAGRAMS . Repair as necessary and retest operation.
- Turn ignition off. Disconnect BCM connectors J2 and J4. Ignition on. Connect test light between ground and Gray 8-pin BCM connector J4 terminal "D" (Orange wire). Also, connect test light between ground and Gray 24-pin BCM connector J2 terminal A10 (Orange wire). See Figure and Figure . If test light illuminates, go to step 5. If test light does not illuminate, go to next step.
- Repair open in appropriate Orange wire between BCM and BCM/CLUSTER fuse (15-amp), or BCM 2 fuse located in underhood fuse block. See WIRING DIAGRAMS . Repair as necessary and retest operation. If Orange wires check okay, go to step 6.
- Connect test light between battery voltage and Gray 8-pin BCM connector terminal "F" (Black wire). If test light illuminates, go to next step. If test light does not illuminate, repair open in Black wire between Gray 8-pin BCM connector terminal "F" and ground. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. If Black wire checks okay, go to next step.
- Check for poor connections to BCM. Repair as necessary. If BCM connections are okay, replace BCM. See BODY CONTROL MODULE under REMOVAL & INSTALLATION. Retest operation.
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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.