Code
P0386
Generic
P — Powertrain
Crankshaft Position Sensor B Circuit Range/Performance
Views:
UK: 17
EN: 27
RU: 22
AI status
Completed
Completed
100%
Causes
- Faulty crankshaft position sensor B (magnetic/VR or Hall type)
- Damaged wiring harness or connector (open, short to power/ground, high resistance)
- Poor sensor air gap or misalignment with reluctor/tone wheel
- Damaged or missing reluctor/tone wheel teeth or debris on reluctor
- Intermittent power, reference or ground to the sensor
- Electrical interference from other circuits or aftermarket devices
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated / CEL on
- Difficulty starting or no‑start condition (intermittent or sustained)
- Engine stalling or rough idle
- Misfires, hesitation or poor acceleration
- Reduced fuel economy
- Intermittent loss of ignition or limp‑in behavior
What to check
- Read and record freeze frame and stored/pendings using an OBD‑II scanner
- Check for other related codes (cam/crank correlation codes)
- Visual inspection of CKP B sensor, connector, and wiring for damage, corrosion or loose pins
- Verify sensor mounting and air gap relative to reluctor/tone wheel
- Backprobe sensor connector to confirm sensor supply voltage and ground present
- Compare live CKP B signal with CKP A (if present) on a scan tool or oscilloscope
Signal parameters
- Hall‑type sensor: square/pulsed waveform, 0–5 V logic levels (switching between ~0 V and ~5 V) with a reference supply (commonly 5 V)
- VR/magnetic sensor: AC sine waveform; amplitude increases with engine speed (typical idle ~0.1–1.5 V AC, higher at rpm)
- Typical DC resistance (inductive/VR sensors): often several hundred to a few thousand ohms (consult vehicle spec)
- Frequency: pulses per engine revolution corresponding to tone wheel tooth count — frequency rises with RPM
- Expected timing: CKP B waveform phase should match expected position relative to CKP A/cam signals (used for synchronization)
Diagnostic algorithm
- Verify code and freeze frame with a scan tool; clear codes and attempt to re‑create fault to confirm reproducibility
- Visually inspect CKP B sensor, harness routing, connector and reluctor/tone wheel for physical damage or contamination
- With key ON (engine off) backprobe sensor connector: confirm reference voltage (Hall) or continuity to sensor ground/power as applicable
- Start engine (if safe) and capture live CKP B signal with an oscilloscope or a scan tool that shows waveform; compare amplitude, shape and timing to CKP A
- If CKP B signal is missing or abnormal, disconnect sensor and measure DC resistance (for VR type) or check switching with an ohm/voltmeter for Hall type — compare to specification where available
- Perform continuity checks and resistance measurements from sensor connector to ECM pins to find opens/shorts/high resistance; wiggle wiring to find intermittent faults
- Inspect and measure sensor air gap; if out of spec, adjust or re‑seat sensor per OEM procedure
- Inspect tone wheel for damaged/missing teeth or debris; repair/replace if damaged; verify timing marks if timing suspected
- If wiring and sensor check good but problem persists, substitute a known good sensor (if available) or test ECM driver outputs and grounds; consider ECM replacement only after all other causes eliminated
Likely causes
- Broken or chafed sensor wire between sensor and ECM
- Corroded connector at the sensor
- Sensor knocked out of position or excessive air gap
- Damaged reluctor/tone ring (missing teeth, bent, debris)
- Failed sensor due to heat or contamination
Fault status
Status
Engine Control Module detected abnormal/crank angle sensor B signal (range or performance). MIL illuminated. Fault stored and may cause drivability issues including rough running, stalling or no‑start.
Repair difficulty: Medium
Diagnostic time: 1.5-4 hours
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Code
P0386
GWM
P — Powertrain
- Incorrect indicator / not adjusted crankshaft position sensor B
Views:
UK: 0
EN: 1
RU: 3
AI status
Completed
Completed
100%
Causes
- Faulty crankshaft position sensor B (magnetic/VR or Hall type)
- Damaged wiring harness or connector (open, short to power/ground, high resistance)
- Poor sensor air gap or misalignment with reluctor/tone wheel
- Damaged or missing reluctor/tone wheel teeth or debris on reluctor
- Intermittent power, reference or ground to the sensor
- Electrical interference from other circuits or aftermarket devices
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated / CEL on
- Difficulty starting or no‑start condition (intermittent or sustained)
- Engine stalling or rough idle
- Misfires, hesitation or poor acceleration
- Reduced fuel economy
- Intermittent loss of ignition or limp‑in behavior
What to check
- Read and record freeze frame and stored/pendings using an OBD‑II scanner
- Check for other related codes (cam/crank correlation codes)
- Visual inspection of CKP B sensor, connector, and wiring for damage, corrosion or loose pins
- Verify sensor mounting and air gap relative to reluctor/tone wheel
- Backprobe sensor connector to confirm sensor supply voltage and ground present
- Compare live CKP B signal with CKP A (if present) on a scan tool or oscilloscope
Signal parameters
- Hall‑type sensor: square/pulsed waveform, 0–5 V logic levels (switching between ~0 V and ~5 V) with a reference supply (commonly 5 V)
- VR/magnetic sensor: AC sine waveform; amplitude increases with engine speed (typical idle ~0.1–1.5 V AC, higher at rpm)
- Typical DC resistance (inductive/VR sensors): often several hundred to a few thousand ohms (consult vehicle spec)
- Frequency: pulses per engine revolution corresponding to tone wheel tooth count — frequency rises with RPM
- Expected timing: CKP B waveform phase should match expected position relative to CKP A/cam signals (used for synchronization)
Diagnostic algorithm
- Verify code and freeze frame with a scan tool; clear codes and attempt to re‑create fault to confirm reproducibility
- Visually inspect CKP B sensor, harness routing, connector and reluctor/tone wheel for physical damage or contamination
- With key ON (engine off) backprobe sensor connector: confirm reference voltage (Hall) or continuity to sensor ground/power as applicable
- Start engine (if safe) and capture live CKP B signal with an oscilloscope or a scan tool that shows waveform; compare amplitude, shape and timing to CKP A
- If CKP B signal is missing or abnormal, disconnect sensor and measure DC resistance (for VR type) or check switching with an ohm/voltmeter for Hall type — compare to specification where available
- Perform continuity checks and resistance measurements from sensor connector to ECM pins to find opens/shorts/high resistance; wiggle wiring to find intermittent faults
- Inspect and measure sensor air gap; if out of spec, adjust or re‑seat sensor per OEM procedure
- Inspect tone wheel for damaged/missing teeth or debris; repair/replace if damaged; verify timing marks if timing suspected
- If wiring and sensor check good but problem persists, substitute a known good sensor (if available) or test ECM driver outputs and grounds; consider ECM replacement only after all other causes eliminated
Likely causes
- Broken or chafed sensor wire between sensor and ECM
- Corroded connector at the sensor
- Sensor knocked out of position or excessive air gap
- Damaged reluctor/tone ring (missing teeth, bent, debris)
- Failed sensor due to heat or contamination
Fault status
Status
Engine Control Module detected abnormal/crank angle sensor B signal (range or performance). MIL illuminated. Fault stored and may cause drivability issues including rough running, stalling or no‑start.
Repair difficulty: Medium
Diagnostic time: 1.5-4 hours
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Code
P0386
HUMMER
P — Powertrain
Crankshaft Position (CKP) Sensor B Performance
Views:
UK: 5
EN: 11
RU: 7
AI status
Completed
Completed
100%
Causes
- Faulty crankshaft position sensor B (magnetic/VR or Hall type)
- Damaged wiring harness or connector (open, short to power/ground, high resistance)
- Poor sensor air gap or misalignment with reluctor/tone wheel
- Damaged or missing reluctor/tone wheel teeth or debris on reluctor
- Intermittent power, reference or ground to the sensor
- Electrical interference from other circuits or aftermarket devices
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated / CEL on
- Difficulty starting or no‑start condition (intermittent or sustained)
- Engine stalling or rough idle
- Misfires, hesitation or poor acceleration
- Reduced fuel economy
- Intermittent loss of ignition or limp‑in behavior
What to check
- Read and record freeze frame and stored/pendings using an OBD‑II scanner
- Check for other related codes (cam/crank correlation codes)
- Visual inspection of CKP B sensor, connector, and wiring for damage, corrosion or loose pins
- Verify sensor mounting and air gap relative to reluctor/tone wheel
- Backprobe sensor connector to confirm sensor supply voltage and ground present
- Compare live CKP B signal with CKP A (if present) on a scan tool or oscilloscope
Signal parameters
- Hall‑type sensor: square/pulsed waveform, 0–5 V logic levels (switching between ~0 V and ~5 V) with a reference supply (commonly 5 V)
- VR/magnetic sensor: AC sine waveform; amplitude increases with engine speed (typical idle ~0.1–1.5 V AC, higher at rpm)
- Typical DC resistance (inductive/VR sensors): often several hundred to a few thousand ohms (consult vehicle spec)
- Frequency: pulses per engine revolution corresponding to tone wheel tooth count — frequency rises with RPM
- Expected timing: CKP B waveform phase should match expected position relative to CKP A/cam signals (used for synchronization)
Diagnostic algorithm
- Verify code and freeze frame with a scan tool; clear codes and attempt to re‑create fault to confirm reproducibility
- Visually inspect CKP B sensor, harness routing, connector and reluctor/tone wheel for physical damage or contamination
- With key ON (engine off) backprobe sensor connector: confirm reference voltage (Hall) or continuity to sensor ground/power as applicable
- Start engine (if safe) and capture live CKP B signal with an oscilloscope or a scan tool that shows waveform; compare amplitude, shape and timing to CKP A
- If CKP B signal is missing or abnormal, disconnect sensor and measure DC resistance (for VR type) or check switching with an ohm/voltmeter for Hall type — compare to specification where available
- Perform continuity checks and resistance measurements from sensor connector to ECM pins to find opens/shorts/high resistance; wiggle wiring to find intermittent faults
- Inspect and measure sensor air gap; if out of spec, adjust or re‑seat sensor per OEM procedure
- Inspect tone wheel for damaged/missing teeth or debris; repair/replace if damaged; verify timing marks if timing suspected
- If wiring and sensor check good but problem persists, substitute a known good sensor (if available) or test ECM driver outputs and grounds; consider ECM replacement only after all other causes eliminated
Likely causes
- Broken or chafed sensor wire between sensor and ECM
- Corroded connector at the sensor
- Sensor knocked out of position or excessive air gap
- Damaged reluctor/tone ring (missing teeth, bent, debris)
- Failed sensor due to heat or contamination
Fault status
Status
Engine Control Module detected abnormal/crank angle sensor B signal (range or performance). MIL illuminated. Fault stored and may cause drivability issues including rough running, stalling or no‑start.
Repair difficulty: Medium
Diagnostic time: 1.5-4 hours
Similar codes
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Was this AI description helpful?
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