Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / B28F2 — Window relay output:short to GND

B28F2 — Window relay output:short to GND

Detailed page for trouble code B28F2.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

B28F2

MITSUBISHI B — Body

Window relay output:short to GND

Brand: MITSUBISHI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or chafed wiring in window relay output circuit contacting chassis ground
  • Corroded or pushed-back connector pins causing short to ground
  • Failed window relay with internal short
  • Faulty window motor drawing excessive current or shorted internally to ground
  • Faulty BCM/body control relay driver (internal short)
  • Water ingress or debris in switch/connector

Symptoms

  • One or more power windows will not operate
  • Windows operate intermittently or only in one direction
  • Fuse or fusible link for window circuit blown repeatedly
  • Relay clicking repeatedly or not engaging
  • DTC B28F2 stored and may accompany other body/window codes
  • Burnt smell or heat at relay, connector or wiring (in severe cases)

What to check

  • Read stored codes and freeze frame data with a scan tool; confirm B28F2 is active
  • Visually inspect window relay, relay socket and wiring harness for burns, melting, corrosion, pin damage or water intrusion
  • Check related fuses and fusible links for continuity
  • Operate the affected window while observing relay and wiring for signs of overheating or arcing
  • Disconnect the window motor and check whether the code clears or behavior changes (isolates motor vs harness)
  • Measure voltage at the BCM/relay output connector with respect to chassis ground with switch operated (expect battery voltage when output is ON)

Signal parameters

  • Expected OFF voltage at relay output: approximately 0 V (open/low) when relay not driven
  • Expected ON voltage at relay output: battery voltage (approx. 12–14 V) when relay driven
  • Continuity between relay output and chassis ground: open / very high resistance when circuit intact
  • Window motor stall current: significantly higher than run current (varies by model); excessive current indicates motor stall/short

Diagnostic algorithm

  1. Retrieve freeze frame and confirm B28F2 is current or stored; note affected windows/circuits.
  2. Visual inspection: check relay, relay socket, connectors, harness through door hinge area and ground points for damage or corrosion; disconnect battery before repairs to harness.
  3. With ignition OFF, disconnect the relay and measure continuity between the relay output pin and chassis ground. If low resistance/short present, trace harness to find short (remove panels as needed).
  4. If no direct short with relay disconnected, reconnect relay and with ignition ON measure voltage at relay output while operating window switch: verify switching to battery voltage. If output stays near 0 V and relay is commanded ON, suspect short or driver fault.
  5. Isolate the motor: disconnect window motor connector. If code clears or outputs return to normal when motor disconnected, bench-test or substitute a known-good motor to confirm motor condition.
  6. Inspect and test relay: swap with identical relay (if available) or bench-test relay for proper operation and internal shorts.
  7. If wiring and motor check good and relay tests normal, test BCM/driver output for internal short or replace BCM as per service manual; consult wiring diagrams and perform pin-level tests.
  8. Repair or replace damaged wiring, connectors, relay or motor as required. Reconnect battery, clear codes, and verify operation through multiple cycles and road test.
  9. After repair, re-scan for codes and monitor the circuit for recurrence.

Likely causes

  • Wiring insulation abrasion at common pinch point (door hinge, harness grommet)
  • Connector terminal bent or touching chassis ground
  • Failed relay contacts or internal relay shorting to ground
  • Window motor internal short or seized motor causing excessive current

Fault status

⚠️ Status
Window relay output circuit detected short to ground by BCM/relay driver. Output expected to switch to battery voltage but is grounded or low.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

B28F0 B28F1 B28F3 B28F4 B2800
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .