B1403

What Does Code B1403 Mean?

DTC B1403 signifies a circuit malfunction within the driver’s side power window ‘up’ switch circuit. This code is typically set by the Body Control Module (BCM), or in some vehicles, a dedicated Door Control Module (DCM), which constantly monitors the electrical signals from the window switches. The control module provides a reference voltage (e.g., 5V or 12V) to the switch and expects to see a specific voltage drop or resistance change when the ‘up’ function of the switch is activated. When the module detects an electrical signal that deviates from its predefined parameters for the ‘up’ circuit – such as an open circuit (infinite resistance), a short to ground (zero resistance), or a short to voltage (constant high voltage) – it interprets this as a fault and logs the B1403 code. This directly impacts the ability to raise the driver’s power window, often rendering the ‘up’ function inoperable or intermittent, while other window functions might remain unaffected.

Common Symptoms

• The driver’s power window fails to move in the ‘up’ direction when the switch is pressed.
• Intermittent operation of the driver’s power window when attempting to move it ‘up’.
• The automatic ‘one-touch up’ feature (if equipped) for the driver’s window is inoperative.
• No audible click or tactile feedback from the switch when attempting to activate the ‘up’ function.
• In some vehicles, other window functions (e.g., ‘down’ or passenger window operation) may still function normally, helping to isolate the fault to the ‘up’ circuit.

What Causes the Code B1403?

• Faulty Driver Power Window Switch Assembly: The most common cause, involving internal electrical or mechanical failure of the ‘up’ contact within the switch itself. This can be due to wear, contamination, or corrosion.
• Wiring Harness Interruption: An open circuit (break) in the wiring between the driver’s window switch and the Body Control Module (BCM) or Door Control Module (DCM). This is particularly common in the flexible wiring harness located within the door jamb due to repeated flexing and stress over time.
• Short Circuit in Wiring: A short to ground or a short to power within the driver’s window ‘up’ switch circuit wiring.
• Corroded or Loose Electrical Connectors: Poor electrical contact at the multi-pin connector for the driver’s window switch or at the connector leading to the BCM/DCM can disrupt the signal.
• Faulty Door Control Module (DCM) or Body Control Module (BCM): While less frequent, an internal malfunction within the module responsible for processing the switch input can also trigger this code.

How to Diagnose and Troubleshoot

Diagnosis of B1403 requires systematic electrical testing:

1. Retrieve and Analyze DTCs: Use an OBD-II scan tool to confirm the B1403 code. Check for any related codes and review freeze frame data, which can provide critical information about the vehicle’s operating conditions when the fault was detected (e.g., voltage, temperature).
2. Visual Inspection:
   • Inspect the driver’s power window switch for any visible damage, contamination, or stuck buttons.
   • Carefully inspect the wiring harness running into the driver’s door, particularly where it passes through the door jamb. Look for any signs of chafing, cuts, or corrosion.
   • Examine the electrical connectors at the back of the window switch and where the harness connects to the BCM/DCM for corrosion, bent pins, or loose connections.
3. Scan Tool Live Data Analysis: If available, access the live data stream for the driver’s window switch inputs via the scan tool. Observe the parameter for the ‘up’ switch position. When the switch is pressed, the data should change state (e.g., from ‘off’ to ‘on’ or a voltage value change). If no change is observed, the fault lies in the switch or its immediate wiring.
4. Digital Multimeter (DMM) Testing at the Switch:
   • Disconnect the Battery: Prioritize safety by disconnecting the vehicle’s battery.
   • Access the Switch Connector: Disconnect the electrical connector from the driver’s power window switch assembly.
   • Continuity Test (Switch Itself): Using a DMM set to continuity or resistance mode, identify the pins for the ‘up’ circuit on the switch side (consult wiring diagrams). Test continuity across these pins. When the ‘up’ switch is pressed, the DMM should indicate continuity (near 0 ohms). When released, it should show an open circuit (OL or infinite resistance). Compare this to the ‘down’ circuit if it is functioning correctly.
   • Voltage and Ground Presence (Harness Side): Reconnect the battery. With the switch connector disconnected from the switch but still connected to the vehicle harness, use the DMM to verify the presence of reference voltage and ground at the appropriate pins of the harness connector (consult wiring diagrams). The control module typically supplies a reference voltage to the switch circuit.
   • Signal Wire Voltage Test (Harness Side): With the battery reconnected and the harness still disconnected from the switch, back-probe the signal wire from the harness connector. This wire usually carries the reference voltage from the module. When the ‘up’ switch (if temporarily reconnected to bypass testing) is activated, this voltage should change significantly (e.g., drop to near 0V or a specific intermediate voltage, depending on the switch design).
5. Circuit Integrity Testing (Wiring Harness): If the switch tests good and power/ground are present at the connector, the issue likely lies within the wiring harness between the switch connector and the BCM/DCM.
   • Continuity Test (Wiring): Disconnect both ends of the suspect wire (at the switch connector and the BCM/DCM connector). Use the DMM to check for continuity along the specific signal wire. An open circuit indicates a break in the wire.
   • Short to Ground/Power Test (Wiring): With both ends disconnected, check for continuity between the signal wire and a known good chassis ground. There should be no continuity. Similarly, check for continuity between the signal wire and any known power wires in the harness.
6. Module Fault: If all wiring, connectors, and the switch itself test perfectly, and the control module is not responding to switch inputs, the BCM or DCM may be faulty. This is generally a last resort diagnosis.

Recommended Repairs and Solutions

• Replace the Driver Power Window Switch Assembly: If diagnostic testing confirms an internal fault within the switch, replacing the complete switch assembly (or just the driver’s side master switch, if it’s a modular unit) is the most common and effective solution. Always use OEM or high-quality aftermarket components.
• Repair or Replace Damaged Wiring: If an open circuit, short to ground, or short to power is identified in the wiring harness, perform a professional repair. This involves splicing in new wire sections using proper soldering techniques, heat-shrink tubing, and ensuring the repair maintains flexibility, especially in door jamb areas. If damage is extensive, consider replacing the entire door harness section.
• Clean and Secure Connectors: If corrosion or loose connections are found, clean the connector terminals thoroughly using electrical contact cleaner and a small brush. Ensure all pins are straight and secure the connectors firmly.
• Replace Door Control Module (DCM) or Body Control Module (BCM): Only proceed with module replacement after unequivocally ruling out the switch, wiring, and connectors. Module replacement often requires specialized programming or coding with a factory-level scan tool to integrate it with the vehicle’s other systems.
• Post-Repair Verification: After completing any repair, clear the DTCs with a scan tool. Operate the driver’s power window through its full range of motion multiple times to ensure the ‘up’ function is fully restored and operates smoothly. If applicable, perform any necessary window motor ‘re-index’ or ‘learn’ procedures that are often required after battery disconnect or component replacement to restore one-touch functionality.