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Home / DTC / P0238 — Turbocharger/Supercharger Boost Sensor A Circuit High

P0238 — Turbocharger/Supercharger Boost Sensor A Circuit High

Detailed page for trouble code P0238.

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11,925generic
23,694specific
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Code

P0238

Generic P — Powertrain

Turbocharger/Supercharger Boost Sensor A Circuit High

Brand: Generic
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
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Code

P0238

GWM P — Powertrain

- High reading of turbocharger sensor A

Brand: GWM
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
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Code

P0238

HUMMER P — Powertrain

Turbocharger Boost Sensor Circuit High Voltage

Brand: HUMMER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
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Code

P0238

ISUZU P — Powertrain

Turbo Charger Boost Sensor Circuit High

Brand: ISUZU
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
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Manual library for ISUZU

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ISUZU

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Code

P0238

LAND ROVER P — Powertrain

Turbocharger / supercharger boost sensor A - high circuit

Brand: LAND ROVER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
413

Browse 413 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

P0238

VOLKSWAGEN P — Powertrain

Turbocharger Boost Sensor 'A' Circuit High

Brand: VOLKSWAGEN
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty boost/MAP sensor (internal short or failure)
  • Short circuit in sensor signal wire to battery voltage or another high-voltage source
  • Poor or corroded connector or pin (intermittent/high resistance on reference or ground)
  • Open or intermittent ground or reference circuit causing false high reading
  • ECM fault or internal input driver failure
  • Actual overboost condition (mechanical wastegate failure) causing legitimate over-range sensor output

Symptoms

  • Malfunction Indicator Lamp (MIL/Check Engine) illuminated
  • Reduced engine performance or limp mode on some vehicles
  • High or erratic boost pressure readings on scan tool or boost gauge
  • Poor drivability, hesitation or surging under boost
  • Possible poor fuel economy

What to check

  • Retrieve freeze frame and live PID data for boost pressure, sensor voltage, reference (5 V) and ground voltages
  • Inspect sensor connector and wiring harness for damage, oil intrusion or corrosion
  • Wiggle test harness while monitoring live data to reproduce voltage changes
  • Measure sensor supply (reference) and ground at connector with key on engine off
  • Check for related codes (MAP/boost sensor low, range/performance, turbo underboost)

Signal parameters

  • Typical reference voltage (Vref): approximately 5.0 V (varies by manufacturer)
  • Expected sensor output: roughly 0.5–4.5 V across operating range (0 kPa to high boost)
  • Ground: near 0 V (less than 0.2 V)
  • ECM input considered 'high' when voltage exceeds expected maximum or defined over-range threshold (varies by vehicle)

Diagnostic algorithm

  1. Note freeze-frame data and record live sensor voltage and calculated boost pressure with key on, engine off and at idle/under boost
  2. Visually inspect sensor and vacuum/boost hoses; remove sensor and check for contamination or obstruction
  3. Backprobe sensor connector: verify Vref (5 V) present with key ON, verify sensor output voltage and ground continuity to chassis and ECM
  4. If Vref is missing or incorrect, trace and repair wiring between ECM and sensor; repair short to battery if present
  5. If Vref and ground are good but output is high, disconnect sensor and measure sensor output with connector disconnected — if output remains high suspect wiring short to voltage or ECM; if it drops to open/expected level, replace sensor
  6. Perform resistance/continuity checks on harness between sensor and ECM; repair any shorts/opens and secure connectors
  7. After repairs, clear codes and road test while monitoring live data to confirm proper sensor behavior and absence of code
  8. If wiring and sensor check good and problem persists, consider ECM input circuit diagnosis or replacement by qualified technician

Likely causes

  • Damaged sensor or contaminated sensing port (oil/soot)
  • Signal wire chafed and shorted to +12 V or constant 5 V reference
  • Loose/corroded connector at sensor causing poor ground or feedback errors
  • Failed sensor reference (5 V) supply from ECM or harness short to battery
  • Excessive boost pressure due to wastegate actuator/solenoid failure

Fault status

⚠️ Status
Boost Sensor A Circuit High — ECM detected voltage/signal above expected range from turbo/supercharger boost sensor A.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.5 hours

Similar codes

P0235 P0236 P0237 P0108 P0299
626

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