* Faulty Wiring or Connector: The most likely culprit is a problem within the wiring harness related to the rear wiper motor or its associated switch. A short, broken wire, or a corroded connector could trigger the CEL indirectly (perhaps through a shared circuit or a general system malfunction). The undocumented code points towards a less common or poorly documented error within this circuit.
* Body Control Module (BCM) Issue: The BCM manages many vehicle functions, including the rear wiper. A malfunctioning BCM might be causing the problem and throwing a confusing code. The undocumented code could be an internal BCM error that hasn't been properly cataloged in the scanner's database.
* Power Supply Problem: A faulty fuse or relay related to the rear wiper circuit could cause intermittent operation and trigger the CEL, potentially through a voltage drop or a system monitoring the power draw.
* Sensor Malfunction (Less Likely): While less probable, a faulty sensor (possibly related to rain sensing, if equipped) could be sending erroneous signals, leading to a wiper-related code and indirectly affecting other systems, hence the CEL.
* Scanner Issue (Least Likely): There's a small chance the scanner itself is misinterpreting the data or has an outdated database. Try a different scanner if possible, though this is less likely given the rear wiper indication.
Troubleshooting Steps:
1. Check the fuses and relays: This is the easiest first step. Consult your owner's manual to locate the fuses and relays associated with the rear wiper motor.
2. Inspect the wiring: Visually examine the wiring harness leading to the rear wiper motor for any signs of damage, corrosion, or loose connections. Pay close attention to the connectors.
3. Test the rear wiper motor directly: If possible, try bypassing the switch and applying power directly to the motor (carefully!) to confirm if the motor itself is faulty.
4. Have a mechanic perform a thorough diagnostic: A qualified mechanic with experience in older vehicles can use advanced diagnostic tools to delve deeper into the undocumented code and pinpoint the problem. They can also test the BCM's functions.
The fact that the rear wiper is working *fine* is puzzling and strengthens the case for a wiring, connector, or BCM problem. The undocumented code is the most significant clue, suggesting a deeper electrical fault that's indirectly causing the CEL. Professional diagnostic help is recommended to resolve this accurately.
