B1241

Step 1: Perform visual inspection of rear wiper washer pump relay, wiring harness from BCM to relay, and all associated connectors for obvious damage, melting, chafing, or corrosion. Pay special attention to areas where harness passes through body panels or near sharp edges.

Step 2: Disconnect the rear washer pump relay and measure voltage at the relay control terminal from the BCM using a digital multimeter. With ignition on and washer switch off, reading should be 0-1V. If battery voltage (12V+) is present, trace the control wire back toward BCM for short to power.

Step 3: With relay still disconnected, check for continuity between the relay control wire and known power sources (fuse box, other circuits) using multimeter in ohms mode. Resistance below 10 ohms indicates a direct short requiring harness repair or replacement.

Step 4: If wiring tests normal, substitute a known good relay and clear codes. Cycle the rear washer function multiple times while monitoring live data for fault return. If code returns immediately, suspect BCM internal failure.

Step 5: Inspect BCM connector for pushed-out pins, corrosion, or moisture intrusion that could cause cross-circuit contamination. Clean and repair connector as needed, apply dielectric grease, and retest system operation after clearing codes.