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Home / DTC / B2878 — Tilt Down Switch Circuit Malfunction

B2878 — Tilt Down Switch Circuit Malfunction

Detailed page for trouble code B2878.

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22,491specific
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Code

B2878

HUMMER B — Body

Tilt Down Switch Circuit Malfunction

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

Causes

  • Failed or worn tilt-down switch
  • Open, short to ground, or short to voltage in the switch wiring
  • Corroded or loose connector at the switch or BCM
  • Blown fuse or intermittent power/ground supply
  • Water intrusion or physical damage to harness or switch
  • Faulty body control module (BCM) or related control module

Symptoms

  • Tilt-down function does not operate when switch is pressed
  • Intermittent operation of tilt-down feature
  • Stored B2878 DTC and possibly related body electrical codes
  • No response from switch or unexpected behavior of tilt mechanism
  • Possible blown fuse for the circuit

What to check

  • Scan the vehicle and record B2878 plus any related DTCs and freeze-frame data
  • Verify battery voltage is stable (9–14 V) and inspect relevant fuses
  • Operate the tilt-down switch while observing scanner data or module inputs
  • Visually inspect switch, connector, and wiring for damage, corrosion, or water
  • Wiggle the wiring harness and connector while watching for changes or freeze-frame updates
  • Check ground connections and power feed to the switch

Signal parameters

  • Reference/power feed to switch: nominal battery voltage (~9–14 V) when key on
  • Switch output: should show continuity (low resistance) to the expected return when actuated
  • Open switch: high resistance/OL; closed switch: near 0 Ω to the return
  • Module input signal toggles when switch is pressed (voltage typically near 0 V or battery voltage depending on design)
  • No module input change or stuck voltage indicates wiring/switch fault

Diagnostic algorithm

  1. Retrieve and record freeze-frame data and any additional DTCs. Confirm B2878 is current or intermittent.
  2. Inspect fuse(s) and relays related to the tilt/comfort system. Replace any blown fuses and retest.
  3. Visually inspect the tilt-down switch, bezel, and harness for damage, moisture, or corrosion. Repair as needed.
  4. With a DVOM or scope, backprobe the switch connector and verify reference power and ground presence with key on.
  5. Operate the switch while measuring the switch signal line to the BCM. Confirm the signal changes as expected (continuity or voltage toggle).
  6. If no signal change, check continuity between switch and module connector; repair any open or shorted wiring.
  7. Repair corroded connectors or poor pin contacts. After repairs, clear codes and re-test function and road-test if applicable.
  8. If wiring and switch test good but code returns, perform module input/output tests per factory manual. Consider BCM repair or replacement as last resort.

Likely causes

  • Failed tilt-down switch (most common)
  • Damaged wiring or broken/shorted conductor between switch and module
  • Connector corrosion or poor pin contact at the switch or module
  • Intermittent power/ground (fuse, splice, or ground strap issue)
  • Less likely: BCM internal fault

Fault status

⚠️ Status
B2878 - Tilt Down Switch Circuit Malfunction. Inspect switch, wiring, power/ground, and related fuses/connectors. Clear code after repair and verify operation.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B2877 B2879 B2880 B2800 B2845
Repair manuals

Manual library for HUMMER

138

Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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Code

B2878

MITSUBISHI B — Body

Pump motor:not connected

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

Causes

  • Failed or worn tilt-down switch
  • Open, short to ground, or short to voltage in the switch wiring
  • Corroded or loose connector at the switch or BCM
  • Blown fuse or intermittent power/ground supply
  • Water intrusion or physical damage to harness or switch
  • Faulty body control module (BCM) or related control module

Symptoms

  • Tilt-down function does not operate when switch is pressed
  • Intermittent operation of tilt-down feature
  • Stored B2878 DTC and possibly related body electrical codes
  • No response from switch or unexpected behavior of tilt mechanism
  • Possible blown fuse for the circuit

What to check

  • Scan the vehicle and record B2878 plus any related DTCs and freeze-frame data
  • Verify battery voltage is stable (9–14 V) and inspect relevant fuses
  • Operate the tilt-down switch while observing scanner data or module inputs
  • Visually inspect switch, connector, and wiring for damage, corrosion, or water
  • Wiggle the wiring harness and connector while watching for changes or freeze-frame updates
  • Check ground connections and power feed to the switch

Signal parameters

  • Reference/power feed to switch: nominal battery voltage (~9–14 V) when key on
  • Switch output: should show continuity (low resistance) to the expected return when actuated
  • Open switch: high resistance/OL; closed switch: near 0 Ω to the return
  • Module input signal toggles when switch is pressed (voltage typically near 0 V or battery voltage depending on design)
  • No module input change or stuck voltage indicates wiring/switch fault

Diagnostic algorithm

  1. Retrieve and record freeze-frame data and any additional DTCs. Confirm B2878 is current or intermittent.
  2. Inspect fuse(s) and relays related to the tilt/comfort system. Replace any blown fuses and retest.
  3. Visually inspect the tilt-down switch, bezel, and harness for damage, moisture, or corrosion. Repair as needed.
  4. With a DVOM or scope, backprobe the switch connector and verify reference power and ground presence with key on.
  5. Operate the switch while measuring the switch signal line to the BCM. Confirm the signal changes as expected (continuity or voltage toggle).
  6. If no signal change, check continuity between switch and module connector; repair any open or shorted wiring.
  7. Repair corroded connectors or poor pin contacts. After repairs, clear codes and re-test function and road-test if applicable.
  8. If wiring and switch test good but code returns, perform module input/output tests per factory manual. Consider BCM repair or replacement as last resort.

Likely causes

  • Failed tilt-down switch (most common)
  • Damaged wiring or broken/shorted conductor between switch and module
  • Connector corrosion or poor pin contact at the switch or module
  • Intermittent power/ground (fuse, splice, or ground strap issue)
  • Less likely: BCM internal fault

Fault status

⚠️ Status
B2878 - Tilt Down Switch Circuit Malfunction. Inspect switch, wiring, power/ground, and related fuses/connectors. Clear code after repair and verify operation.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B2877 B2879 B2880 B2800 B2845
406

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

MITSUBISHI

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

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