Code
B1287
ALFA ROMEO
B — Body
Left air intake potentiometer servo short to ground
Views:
UK: 5
EN: 6
RU: 2
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring shorting the potentiometer signal to chassis ground
- Corroded or water-damaged connector at the left air intake servo/potentiometer
- Failed potentiometer/servo assembly with internal short
- Poor ground or short caused by nearby aftermarket accessories or repairs
- Faulty climate control module (rare)
Symptoms
- HVAC intake mode (recirculation/fresh air) not switching or stuck in one position
- Blower control or automatic climate functions may show incorrect behavior
- DTC B1287 stored and may disable automatic intake control
- Possible audible clicking from servo if moving but feedback not detected
What to check
- Read DTCs and freeze frame with a scan tool; record related HVAC codes
- Visual inspection of left intake servo connector and wiring harness for damage, corrosion, or water ingress
- Wiggle-test harness while monitoring code status or live data to reproduce fault
- Backprobe potentiometer signal, reference and ground with multimeter/oscilloscope while operating intake command
- Measure continuity between signal wire and chassis ground with connector disconnected
Signal parameters
- Reference voltage to potentiometer: typically 5 V (verify exact spec for vehicle)
- Signal output (potentiometer): 0.0–5.0 V depending flap position — normally varies smoothly as actuator moves
- Ground: near 0 V chassis ground
- Potentiometer resistance typically in the kiloohm range (approx. 2–10 kΩ) — check OEM spec
Diagnostic algorithm
- Confirm code: connect scan tool, read B1287 and any related HVAC codes; record live data for the left intake potentiometer while commanding intake flap.
- Visual inspection: with ignition off inspect connector, pins and harness for damage, corrosion, water, or pin displacement; repair or clean as required.
- Connector check: disconnect left intake servo connector; check for continuity between the potentiometer signal wire and chassis ground — there should be no direct short. If short exists, trace and repair wiring.
- Voltage check: backprobe reference, signal and ground with ignition ON and while commanding the intake flap. Verify reference voltage (≈5 V), ground (0 V) and that the signal varies when actuator moves.
- Wiggle test: with connector attached and monitoring live data, move harness and actuator to check for intermittent shorts or contact faults.
- Component isolation: if wiring and connector are good but signal remains shorted, remove/replace the left air intake potentiometer/servo and re-test.
- Finalize: clear codes, operate HVAC through full range and re-scan to confirm fault is gone. If code returns and wiring & actuator check OK, consider module-level fault and pursue module diagnostics.
Likely causes
- Wiring abrasion where harness passes through bulkhead or HVAC housing
- Connector pins pushed out, bent or corroded allowing contact with ground
- HVAC unit moisture intrusion causing shorting of the potentiometer element
- Failed potentiometer inside the servo unit
Fault status
Status
Left air intake potentiometer servo — signal shorted to ground (B1287)
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
B1287
FIAT
B — Body
Left air intake potentiometer servo short to ground
Views:
UK: 5
EN: 5
RU: 2
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring shorting the potentiometer signal to chassis ground
- Corroded or water-damaged connector at the left air intake servo/potentiometer
- Failed potentiometer/servo assembly with internal short
- Poor ground or short caused by nearby aftermarket accessories or repairs
- Faulty climate control module (rare)
Symptoms
- HVAC intake mode (recirculation/fresh air) not switching or stuck in one position
- Blower control or automatic climate functions may show incorrect behavior
- DTC B1287 stored and may disable automatic intake control
- Possible audible clicking from servo if moving but feedback not detected
What to check
- Read DTCs and freeze frame with a scan tool; record related HVAC codes
- Visual inspection of left intake servo connector and wiring harness for damage, corrosion, or water ingress
- Wiggle-test harness while monitoring code status or live data to reproduce fault
- Backprobe potentiometer signal, reference and ground with multimeter/oscilloscope while operating intake command
- Measure continuity between signal wire and chassis ground with connector disconnected
Signal parameters
- Reference voltage to potentiometer: typically 5 V (verify exact spec for vehicle)
- Signal output (potentiometer): 0.0–5.0 V depending flap position — normally varies smoothly as actuator moves
- Ground: near 0 V chassis ground
- Potentiometer resistance typically in the kiloohm range (approx. 2–10 kΩ) — check OEM spec
Diagnostic algorithm
- Confirm code: connect scan tool, read B1287 and any related HVAC codes; record live data for the left intake potentiometer while commanding intake flap.
- Visual inspection: with ignition off inspect connector, pins and harness for damage, corrosion, water, or pin displacement; repair or clean as required.
- Connector check: disconnect left intake servo connector; check for continuity between the potentiometer signal wire and chassis ground — there should be no direct short. If short exists, trace and repair wiring.
- Voltage check: backprobe reference, signal and ground with ignition ON and while commanding the intake flap. Verify reference voltage (≈5 V), ground (0 V) and that the signal varies when actuator moves.
- Wiggle test: with connector attached and monitoring live data, move harness and actuator to check for intermittent shorts or contact faults.
- Component isolation: if wiring and connector are good but signal remains shorted, remove/replace the left air intake potentiometer/servo and re-test.
- Finalize: clear codes, operate HVAC through full range and re-scan to confirm fault is gone. If code returns and wiring & actuator check OK, consider module-level fault and pursue module diagnostics.
Likely causes
- Wiring abrasion where harness passes through bulkhead or HVAC housing
- Connector pins pushed out, bent or corroded allowing contact with ground
- HVAC unit moisture intrusion causing shorting of the potentiometer element
- Failed potentiometer inside the servo unit
Fault status
Status
Left air intake potentiometer servo — signal shorted to ground (B1287)
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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Send to email
Code
B1287
Other
B — Body
Servo Motor Potentiometer Airintake Left Circuit Short To Ground
Views:
UK: 17
EN: 21
RU: 21
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring shorting the potentiometer signal to chassis ground
- Corroded or water-damaged connector at the left air intake servo/potentiometer
- Failed potentiometer/servo assembly with internal short
- Poor ground or short caused by nearby aftermarket accessories or repairs
- Faulty climate control module (rare)
Symptoms
- HVAC intake mode (recirculation/fresh air) not switching or stuck in one position
- Blower control or automatic climate functions may show incorrect behavior
- DTC B1287 stored and may disable automatic intake control
- Possible audible clicking from servo if moving but feedback not detected
What to check
- Read DTCs and freeze frame with a scan tool; record related HVAC codes
- Visual inspection of left intake servo connector and wiring harness for damage, corrosion, or water ingress
- Wiggle-test harness while monitoring code status or live data to reproduce fault
- Backprobe potentiometer signal, reference and ground with multimeter/oscilloscope while operating intake command
- Measure continuity between signal wire and chassis ground with connector disconnected
Signal parameters
- Reference voltage to potentiometer: typically 5 V (verify exact spec for vehicle)
- Signal output (potentiometer): 0.0–5.0 V depending flap position — normally varies smoothly as actuator moves
- Ground: near 0 V chassis ground
- Potentiometer resistance typically in the kiloohm range (approx. 2–10 kΩ) — check OEM spec
Diagnostic algorithm
- Confirm code: connect scan tool, read B1287 and any related HVAC codes; record live data for the left intake potentiometer while commanding intake flap.
- Visual inspection: with ignition off inspect connector, pins and harness for damage, corrosion, water, or pin displacement; repair or clean as required.
- Connector check: disconnect left intake servo connector; check for continuity between the potentiometer signal wire and chassis ground — there should be no direct short. If short exists, trace and repair wiring.
- Voltage check: backprobe reference, signal and ground with ignition ON and while commanding the intake flap. Verify reference voltage (≈5 V), ground (0 V) and that the signal varies when actuator moves.
- Wiggle test: with connector attached and monitoring live data, move harness and actuator to check for intermittent shorts or contact faults.
- Component isolation: if wiring and connector are good but signal remains shorted, remove/replace the left air intake potentiometer/servo and re-test.
- Finalize: clear codes, operate HVAC through full range and re-scan to confirm fault is gone. If code returns and wiring & actuator check OK, consider module-level fault and pursue module diagnostics.
Likely causes
- Wiring abrasion where harness passes through bulkhead or HVAC housing
- Connector pins pushed out, bent or corroded allowing contact with ground
- HVAC unit moisture intrusion causing shorting of the potentiometer element
- Failed potentiometer inside the servo unit
Fault status
Status
Left air intake potentiometer servo — signal shorted to ground (B1287)
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email