B1816

What does B1816 mean?

B-code B1816 means "Wiper Rear Motor Down Relay Coil Circuit Short To Battery". It is a manufacturer-specific diagnostic trouble code (DTC) in the body electronics. The circuit has a short to battery voltage, meaning an unintended connection to the positive supply rail exists in the wiper rear motor down relay coil circuit short to battery wiring. This warning should be addressed within the next few days to avoid further damage. This code applies to OBD-II compliant electric and hybrid vehicles.

Possible Causes

• Chafed or pinched wire making contact with a positive voltage supply
• Water or moisture intrusion into the connector causing a voltage leak
• Faulty module or sensor internally shorted to battery
• Incorrectly installed aftermarket accessory creating a voltage path

Recommended Actions

1. 1 Avoid aggressive driving and schedule a diagnostic appointment within the next 1–3 days
2. 2 Scan for all DTCs with an OBD-II scanner — note any related codes stored alongside B1816
3. 3 Inspect wiring harness for chafed insulation, pinched wires, or contact with metal surfaces
4. 4 Measure voltage/resistance at the connector with the harness disconnected to locate the short
5. 5 Clear the DTC, road-test the vehicle, and re-scan to confirm whether the fault returns
6. 6 If the fault persists after inspection and clearing, consult an EV-certified technician for component replacement

Related Body fault codes