B1398 — Driver Power Window One Touch Window Relay Circuit Failure #

The code label may vary depending on the vehicle manufacturer (OEM). See below for known description variations by brand.

• Ford: Driver Power Window One Touch Up/Down Relay Circuit Failure
• Toyota: Driver’s Power Window Auto Relay Circuit Malfunction
• Honda: Driver’s Window One-Touch Relay Circuit Fault
• GM: Driver Power Window Express Relay Circuit Error

Summary of code B1398 #

The B1398 diagnostic trouble code (DTC) refers to a malfunction detected in the Driver Power Window One Touch Window Relay Circuit. This circuit is responsible for enabling the “one-touch” or “express” function, allowing the driver’s window to roll up or down automatically with a single press or pull of the switch. When the vehicle’s control module (often the Body Control Module, BCM) senses an electrical fault—such as an open, short, or out-of-range signal—within this relay circuit, it triggers the B1398 code. This is a body system code, not an engine-related code, and is commonly detected via OBD-II/EOBD compliant scanners. While not critical for safety, it can affect convenience and vehicle functionality.

Common symptoms for code B1398 #

A vehicle experiencing the B1398 code will typically show clear signs related to the driver’s power window operation. The primary symptom is the loss or erratic behavior of the “one-touch” window function, but other issues may manifest. Here’s what you may notice:

• One-touch up or down feature for the driver’s window does not work
• Driver’s window only operates in manual (hold switch) mode
• Window may stop or reverse unexpectedly during auto operation
• Window relay may click audibly but window does not move
• In some cases, complete inoperability of the driver’s window
• Intermittent or erratic window movement
• Body Control Module (BCM) may set other related codes

Most probable causes for code B1398 #

Several factors can trigger the B1398 code, but some are more common than others. Understanding the likely causes helps streamline the diagnostic process and target repairs efficiently. Probable causes, in order of frequency, include:

1. Faulty driver power window one-touch relay — The relay itself may be defective, stuck, or have burned contacts.
2. Wiring issues — Damaged, corroded, or loose wiring/connectors in the power window relay circuit.
3. Malfunctioning driver window switch — Internal failure or poor contact in the switch assembly.
4. Faulty Body Control Module (BCM) — In rare cases, a problem with the BCM can affect relay operation.
5. Window motor or regulator problems — Excessive current draw or mechanical binding may cause electrical faults detected by the relay circuit.

Step-by-step diagnostics for code B1398 #

Effective diagnosis of the B1398 code requires a systematic approach. Following these steps will help pinpoint the root cause without unnecessary parts replacement or wasted time:

1. Verify the code: Use a scan tool to confirm B1398 and check for any related codes (especially in the BCM).
2. Function test: Operate the driver’s window switch—note if manual and/or one-touch features work or fail.
3. Visual inspection: Check wiring and connectors at the window switch, relay, and motor for damage, corrosion, or loose pins.
4. Test the relay: Using a wiring diagram, test the one-touch relay for proper operation (listen for clicks, measure voltage at relay terminals).
5. Inspect the switch: Test the driver’s window switch for continuity and proper function using a multimeter.
6. Check window motor/regulator: Ensure the window mechanism is not binding and the motor is not drawing excessive current.
7. Evaluate the BCM: If all other components check out, test or substitute the BCM (if possible) per OEM procedures.
8. Clear codes and test: After repairs, clear the DTC and retest the window operation to confirm the fix.

Possible repairs for code B1398 #

Repairing the B1398 code will depend on the specific fault found during diagnosis. Addressing the root cause is key to a lasting solution. Typical repairs include:

• Replacing a faulty driver power window one-touch relay
• Repairing or replacing damaged wiring and connectors in the power window circuit
• Replacing the driver’s window switch if confirmed faulty
• Repairing or replacing the window motor or regulator assembly if mechanically binding or drawing excess current
• In rare cases, reprogramming or replacing the Body Control Module (BCM)

Is it safe to drive with code B1398? #

Yes, it is generally safe to drive with code B1398 present, as this code affects convenience features (specifically, the automatic operation of the driver’s window) rather than critical safety or drivability systems. However, if the window is stuck open or closed, it could impact comfort, security, or visibility—especially in adverse weather or emergency situations. For this reason, prompt attention is recommended even though the vehicle remains safe to operate.

Vehicles most commonly affected by code B1398 #

While the B1398 code can appear in any vehicle equipped with an auto/one-touch driver window feature, it is most frequently reported in the following OEM brands and models:

• Ford (Fusion, Focus, F-150, Escape)
• Toyota (Camry, Corolla, RAV4)
• Honda (Civic, Accord, CR-V)
• General Motors (Chevrolet Malibu, Silverado, Equinox)
• Mazda (Mazda3, Mazda6, CX-5)

This list is not exhaustive; any vehicle with a driver’s one-touch window relay circuit can potentially set code B1398.

Common mistakes & best practices for code B1398 #

Misdiagnosing B1398 can lead to unnecessary repairs or repeated failures. Avoid these pitfalls and follow best practices for reliable results:

• Replacing the window switch or motor without testing the relay and its circuit first
• Overlooking damaged or corroded wiring/connectors, especially in the door harness flex point
• Resetting/clearing the code without identifying and fixing the root cause
• Neglecting to check for related codes (other body or communication DTCs)
• Using non-OEM parts that may not meet the vehicle’s electrical specifications

Quick FAQ for code B1398 #

Have questions about code B1398? Here are the answers to the most common concerns:

• Q: Will disconnecting the battery clear the B1398 code?
  A: No, disconnecting the battery may temporarily erase the code, but it will return if the underlying problem persists.
• Q: Can I fix B1398 by lubricating the window tracks?
  A: While lubrication can help if the window is binding, B1398 specifically refers to an electrical circuit fault; mechanical fixes alone are unlikely to resolve it unless excess resistance is causing the fault.
• Q: Does B1398 mean my Body Control Module (BCM) is bad?
  A: Not usually. The BCM is rarely the root cause. Most issues are with the relay, switch, or wiring.