B3802 – Parklamps Request Circuit

System: Body | Standard: ISO/SAE Controlled | Fault type: Circuit

Definition source: SAE J2012 naming/structure guidance

What Does B3802 Mean?

B3802 – Parklamps Request Circuit is an ISO/SAE controlled Body diagnostic trouble code that indicates a circuit fault in the electrical path used to carry the parklamps request. In other words, the module responsible for monitoring the parklamps request has detected that the request circuit is not behaving electrically as expected (for example, an open, short, high resistance, or an implausible electrical state).

This code does not, by itself, identify a single failed component. It identifies the Parklamps Request Circuit as the problem area. The fault may be within the switch/input side, the wiring/connectors, or the module input circuitry, depending on the vehicle’s circuit design.

Quick Reference

• Code: B3802
• Official title: B3802 – Parklamps Request Circuit
• System: Body
• Standard classification: ISO/SAE Controlled
• Fault type: Circuit
• What it indicates: The parklamps request circuit has an electrical fault as detected by the monitoring module
• What to prioritize: Verify request input behavior, then inspect/test wiring, connectors, power/ground as applicable, and module input integrity

Symptoms

A B3802 fault can affect how the parking lamps respond to a request. Possible symptoms include:

• Park lamps do not turn on when requested
• Park lamps do not turn off when the request is removed
• Intermittent operation (request works sometimes and fails at other times)
• Incorrect response to the lighting switch/input (request state does not match expected lamp behavior)
• Stored DTC B3802 found during a scan, possibly along with other Body-related lighting codes

Common Causes

Because B3802 is defined as a circuit fault in the Parklamps Request Circuit, common causes are electrical issues in the request signal path:

• Open circuit in the parklamps request wiring (broken conductor, disconnected connector)
• High resistance in the request circuit (damaged wire strands, poor splice, weak terminal contact)
• Short to ground on the request circuit
• Short to voltage on the request circuit
• Connector/terminal problems (corrosion, moisture intrusion, loose terminal tension, backed-out pins)
• Fault in the parklamps request input device (if the request originates from a switch or input unit and it does not produce the correct electrical signal)
• Module-side input circuit issue (if the request signal arrives correctly but the module cannot interpret it due to an internal input fault)
• Power or ground issues that prevent the request circuit from reaching valid electrical states (where applicable to the circuit design)

Diagnosis Steps

Use a scan tool that can access Body systems and live data, a digital multimeter, and the correct wiring diagram for the specific vehicle. The goal is to confirm whether the parklamps request circuit can produce and carry the expected electrical signal from the request source to the monitoring module.

1. Confirm the code and context. Retrieve B3802 and record any available snapshot/freeze-frame information. Note whether the code is current, pending, or history. Clear the code and operate the lighting request (as applicable) to see whether B3802 resets.
2. Check for additional related codes. If other Body or lighting-related DTCs are present, address shared electrical issues first (such as shared connectors, harness routes, power feeds, or grounds) before focusing narrowly on a single circuit.
3. Verify the symptom. Command the parklamps request through the normal control method and observe whether parking lamps respond correctly. Confirm whether the issue is “always,” “never,” or intermittent.
4. Inspect the request circuit components and harness routing. Perform a careful visual inspection of the wiring and connectors associated with the parklamps request circuit. Look for damage, pinched sections, rubbed-through insulation, water intrusion, or terminals that appear overheated or distorted.
5. Check connectors and terminals closely. Disconnect and inspect relevant connectors for corrosion, moisture, bent pins, backed-out pins, or looseness. Confirm connector locks are fully engaged and that terminals have proper retention/tension.
6. Use scan tool data to evaluate the request input (if available). Locate the parklamps request-related data parameter(s) in live data. Toggle the request and confirm whether the module reports a clean, repeatable change of state. If the parameter does not change while the request is operated, a circuit fault is likely upstream or at the module input.
7. Measure the request signal electrically at the module input. With the wiring diagram as a guide, back-probe the request circuit at the module connector (using appropriate techniques to avoid terminal damage). Toggle the request and verify the signal transitions as expected for that circuit design. A signal that is stuck, unstable, or out of range supports a circuit fault diagnosis.
8. Isolate wiring faults with continuity and short testing. With power off (and modules protected per service information), check continuity of the request circuit end-to-end. Then test for short to ground and short to voltage. If the issue is intermittent, perform careful harness movement while monitoring measurements to locate an intermittent open or short.
9. Verify supporting power/ground where applicable. Some request circuits depend on specific reference voltages, pull-up/pull-down strategies, or dedicated power/ground paths. Confirm required feeds and grounds are within specification and stable, and correct any voltage drop issues found.
10. Evaluate module input integrity only after the circuit is proven. If the request signal is correct at the module connector but the module data does not reflect it and B3802 resets, re-check module power/grounds and connector condition. If all external circuit tests pass, the module input circuitry may be suspect.
11. Confirm the repair. After repairs, clear codes and perform repeated functional checks of the parklamps request. Re-scan for pending/current codes to verify B3802 does not return.

Possible Fixes

• Repair or replace damaged wiring in the Parklamps Request Circuit (open/high resistance sections, rubbed-through insulation)
• Repair connector/terminal issues (clean corrosion, address moisture intrusion, restore terminal tension, replace damaged terminals, ensure correct pin fitment)
• Correct shorts to ground or voltage affecting the request circuit (locate chafing, pinched harness, or incorrect connections)
• Restore required power/ground for the request circuit or related input circuitry (repair feeds, grounds, splices, or connection points as required by the wiring design)
• Replace the parklamps request input device only if testing proves it cannot produce the correct electrical request signal
• Address module-side issues only after confirming the circuit is electrically correct at the module connector and that module power/grounds are good

Can I Still Drive With B3802?

The vehicle may still be drivable, but B3802 can affect exterior lighting operation because it involves the Parklamps Request Circuit. If the parking lamps do not turn on when needed, do not turn off when they should, or operate intermittently, the vehicle may be less visible in low-light conditions and may create a battery drain risk if lamps stay on unexpectedly.

Before driving, verify that exterior lighting functions correctly for current conditions. If the parking lamps cannot be relied upon, limit driving in low visibility until the circuit fault is diagnosed and repaired.

Repair Costs

Repair cost depends on whether the confirmed root cause is wiring, connector condition, a switch or module issue, or the labor needed to diagnose the fault correctly.