P0375: Timing Reference High Resolution Signal B Malfunction
Can cause poor engine performance, misfires, stalling, difficulty starting, or no start due to incorrect timing reference
Overview
P0375 indicates a malfunction of the high resolution timing reference signal B circuit often tied to crankshaft or camshaft position sensor 'B', affecting engine speed/position detection
Common Symptoms
- Illuminated check engine light
- Engine may crank but not start or hard start
- Rough idle or misfires
- Stalling or hesitation under acceleration
- Reduced power or erratic performance
Most Common Causes
Sensor damage or failure often triggers the incorrect or missing timing reference signal
Corroded, broken, or shorted wires/connectors can disrupt signal integrity
Missing teeth or debris on the reluctor wheel can distort the high resolution signal
Timing chain/belt wear or misalignment can cause synchronization errors leading to P0375
Rare but possible internal control module malfunction affecting signal interpretation
Diagnostic Steps
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Use a professional OBD-II scan tool to confirm P0375 and check for related codesExpected: Code P0375 present; possible additional codes relating to cam/crank position sensorsInterpretation: Confirms timing reference signal issue and detects related sensor faults
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Perform a visual inspection of sensor B (crankshaft or camshaft) wiring and connectorsExpected: No corrosion, breaks, or loose connectionsInterpretation: Damaged or loose wiring likely cause if abnormalities found
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Test sensor B signal with a multimeter or oscilloscope during engine crank/runExpected: Fluctuating voltage signal corresponding to engine movementInterpretation: Stable signal indicates functional sensor; lack or erratic signal suggests sensor or wiring fault
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Inspect reluctor/trigger wheel on cam/crank for damage or missing teethExpected: Intact reluctor wheel with uniform teethInterpretation: Irregularities can distort the high resolution signal and trigger the code
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Check timing belt/chain alignment per OEM specificationExpected: Proper alignment and tensionInterpretation: Misalignment can lead to signal synchronization errors
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If all tests pass, evaluate ECM/PCM communication and software for faultsExpected: Proper ECM signaling and firmware versionInterpretation: Faulty ECM or outdated software if anomalies seen
Repair Solutions
Use OEM or high‑quality sensor; verify cause before replacement
Cost varies with labor needed for access and wiring complexity
Repair cost depends on extent of timing component damage
Consider only after ruling out sensor and wiring issues
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Confusing P0375 with similar codes like P0365/P0366 which relate to camshaft position sensor circuits without high resolution signal context
- Attributing rough engine behavior to fuel or ignition misfires without verifying timing reference signal integrity
- Replacing incorrect sensor (A instead of B) due to misinterpretation of code definition
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