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Home / DTC / P0255 — Injection Pump Fuel Metering Control A Intermittent (Cam/Rotor/Injector)

P0255 — Injection Pump Fuel Metering Control A Intermittent (Cam/Rotor/Injector)

Detailed page for trouble code P0255.

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23,694specific
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P0255

Generic P — Powertrain

Injection Pump Fuel Metering Control A Intermittent (Cam/Rotor/Injector)

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

Causes

  • Damaged or corroded connector at the injection pump fuel metering/actuator
  • Broken, shorted or intermittent wiring (open, short to ground, short to battery) in the control circuit
  • Faulty injection pump metering valve/actuator or internal pump electronics
  • Poor or intermittent ground or battery supply to pump or PCM
  • PCM/ECM software or internal fault
  • Intermittent connection at body harness clips or contact points

Symptoms

  • Malfunction Indicator Lamp (MIL) illumination
  • Hard starting or extended cranking
  • Rough idle, stalling or misfire-like symptoms
  • Reduced engine power or limp-home mode
  • Increased smoke or abnormal exhaust
  • Poor fuel economy or surging under load

What to check

  • Read and record freeze frame data and stored related codes with a scan tool
  • Check for additional fuel-related codes (fuel rail pressure, injectors, pump control)
  • Visually inspect wiring and connectors at the injection pump and PCM for corrosion, damage, or loose pins
  • Backprobe the pump control connector and observe voltage and signal while commanding the actuator with a scan tool
  • Wiggle the harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery voltage and engine grounds for proper connections and continuity

Signal parameters

  • Control type: typically a PWM (pulse-width modulated) command from PCM to pump metering actuator
  • Expected command: variable duty cycle (0–100%) depending on engine load/conditions
  • Connector voltage when commanded ON: near battery voltage; when commanded OFF: low (close to 0 V) or PWM switching
  • Coil/actuator resistance: design-specific — consult vehicle service data; large deviations indicate fault
  • PWM frequency: design-specific (commonly tens to several hundred Hz) — irregular or missing waveform indicates problem

Diagnostic algorithm

  1. Retrieve freeze frame and all stored codes. Note conditions when code set (engine temp, RPM, load).
  2. Visually inspect the pump connector and harness for corrosion, bent pins, chafing, or repairs. Repair any obvious damage before further testing.
  3. Check battery voltage and main engine grounds. Clean and tighten ground points and battery connections as needed.
  4. Backprobe the pump control 'A' connector. With ignition ON and engine OFF, measure voltage at the supply pin and resistance of the actuator if accessible; compare to specs.
  5. With a scan tool, command the fuel metering actuator while monitoring the actual signal. Look for proper response and stable duty cycle. Observe for intermittent loss or erratic duty.
  6. Wiggle/shift harness and connectors while monitoring the live signal to reproduce intermittent behavior. Inspect any cover grommets or flex points for damage.
  7. Use an oscilloscope to inspect waveform for correct PWM frequency and clean edges. Look for noise, dropouts, or voltage spikes.
  8. If wiring and connector check good but signal still intermittent, substitute or bench-test the pump actuator (if serviceable) or replace injection pump assembly per manufacturer procedure.
  9. If actuator and harness test good, consider PCM output test or reflashing as last resort — confirm with manufacturer diagnostics before replacing PCM.
  10. After repairs, clear codes and road test under conditions similar to freeze frame. Re-scan to confirm code does not return.

Likely causes

  • Corroded/loose connector at fuel metering actuator (most common)
  • Damaged wiring harness where it flexes or routes near moving parts
  • Failing injection pump solenoid/actuator
  • Intermittent ground or low battery voltage during cranking
  • PCM/ECM intermittent output (less common)

Fault status

⚠️ Status
Intermittent fault detected in Injection Pump Fuel Metering Control A circuit. Irregular or missing control signal to the pump metering actuator was observed by the PCM.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours
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Code

P0255

GWM P — Powertrain

- Malfunction of the fuel sensor A of the injector pump (Cam / Rotor / Nozzle)

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

Causes

  • Damaged or corroded connector at the injection pump fuel metering/actuator
  • Broken, shorted or intermittent wiring (open, short to ground, short to battery) in the control circuit
  • Faulty injection pump metering valve/actuator or internal pump electronics
  • Poor or intermittent ground or battery supply to pump or PCM
  • PCM/ECM software or internal fault
  • Intermittent connection at body harness clips or contact points

Symptoms

  • Malfunction Indicator Lamp (MIL) illumination
  • Hard starting or extended cranking
  • Rough idle, stalling or misfire-like symptoms
  • Reduced engine power or limp-home mode
  • Increased smoke or abnormal exhaust
  • Poor fuel economy or surging under load

What to check

  • Read and record freeze frame data and stored related codes with a scan tool
  • Check for additional fuel-related codes (fuel rail pressure, injectors, pump control)
  • Visually inspect wiring and connectors at the injection pump and PCM for corrosion, damage, or loose pins
  • Backprobe the pump control connector and observe voltage and signal while commanding the actuator with a scan tool
  • Wiggle the harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery voltage and engine grounds for proper connections and continuity

Signal parameters

  • Control type: typically a PWM (pulse-width modulated) command from PCM to pump metering actuator
  • Expected command: variable duty cycle (0–100%) depending on engine load/conditions
  • Connector voltage when commanded ON: near battery voltage; when commanded OFF: low (close to 0 V) or PWM switching
  • Coil/actuator resistance: design-specific — consult vehicle service data; large deviations indicate fault
  • PWM frequency: design-specific (commonly tens to several hundred Hz) — irregular or missing waveform indicates problem

Diagnostic algorithm

  1. Retrieve freeze frame and all stored codes. Note conditions when code set (engine temp, RPM, load).
  2. Visually inspect the pump connector and harness for corrosion, bent pins, chafing, or repairs. Repair any obvious damage before further testing.
  3. Check battery voltage and main engine grounds. Clean and tighten ground points and battery connections as needed.
  4. Backprobe the pump control 'A' connector. With ignition ON and engine OFF, measure voltage at the supply pin and resistance of the actuator if accessible; compare to specs.
  5. With a scan tool, command the fuel metering actuator while monitoring the actual signal. Look for proper response and stable duty cycle. Observe for intermittent loss or erratic duty.
  6. Wiggle/shift harness and connectors while monitoring the live signal to reproduce intermittent behavior. Inspect any cover grommets or flex points for damage.
  7. Use an oscilloscope to inspect waveform for correct PWM frequency and clean edges. Look for noise, dropouts, or voltage spikes.
  8. If wiring and connector check good but signal still intermittent, substitute or bench-test the pump actuator (if serviceable) or replace injection pump assembly per manufacturer procedure.
  9. If actuator and harness test good, consider PCM output test or reflashing as last resort — confirm with manufacturer diagnostics before replacing PCM.
  10. After repairs, clear codes and road test under conditions similar to freeze frame. Re-scan to confirm code does not return.

Likely causes

  • Corroded/loose connector at fuel metering actuator (most common)
  • Damaged wiring harness where it flexes or routes near moving parts
  • Failing injection pump solenoid/actuator
  • Intermittent ground or low battery voltage during cranking
  • PCM/ECM intermittent output (less common)

Fault status

⚠️ Status
Intermittent fault detected in Injection Pump Fuel Metering Control A circuit. Irregular or missing control signal to the pump metering actuator was observed by the PCM.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours
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Code

P0255

HUMMER P — Powertrain

Injection Pump Fuel Metering Control "A" Intermittent (Cam/Rotor/Injector)

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

Causes

  • Damaged or corroded connector at the injection pump fuel metering/actuator
  • Broken, shorted or intermittent wiring (open, short to ground, short to battery) in the control circuit
  • Faulty injection pump metering valve/actuator or internal pump electronics
  • Poor or intermittent ground or battery supply to pump or PCM
  • PCM/ECM software or internal fault
  • Intermittent connection at body harness clips or contact points

Symptoms

  • Malfunction Indicator Lamp (MIL) illumination
  • Hard starting or extended cranking
  • Rough idle, stalling or misfire-like symptoms
  • Reduced engine power or limp-home mode
  • Increased smoke or abnormal exhaust
  • Poor fuel economy or surging under load

What to check

  • Read and record freeze frame data and stored related codes with a scan tool
  • Check for additional fuel-related codes (fuel rail pressure, injectors, pump control)
  • Visually inspect wiring and connectors at the injection pump and PCM for corrosion, damage, or loose pins
  • Backprobe the pump control connector and observe voltage and signal while commanding the actuator with a scan tool
  • Wiggle the harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery voltage and engine grounds for proper connections and continuity

Signal parameters

  • Control type: typically a PWM (pulse-width modulated) command from PCM to pump metering actuator
  • Expected command: variable duty cycle (0–100%) depending on engine load/conditions
  • Connector voltage when commanded ON: near battery voltage; when commanded OFF: low (close to 0 V) or PWM switching
  • Coil/actuator resistance: design-specific — consult vehicle service data; large deviations indicate fault
  • PWM frequency: design-specific (commonly tens to several hundred Hz) — irregular or missing waveform indicates problem

Diagnostic algorithm

  1. Retrieve freeze frame and all stored codes. Note conditions when code set (engine temp, RPM, load).
  2. Visually inspect the pump connector and harness for corrosion, bent pins, chafing, or repairs. Repair any obvious damage before further testing.
  3. Check battery voltage and main engine grounds. Clean and tighten ground points and battery connections as needed.
  4. Backprobe the pump control 'A' connector. With ignition ON and engine OFF, measure voltage at the supply pin and resistance of the actuator if accessible; compare to specs.
  5. With a scan tool, command the fuel metering actuator while monitoring the actual signal. Look for proper response and stable duty cycle. Observe for intermittent loss or erratic duty.
  6. Wiggle/shift harness and connectors while monitoring the live signal to reproduce intermittent behavior. Inspect any cover grommets or flex points for damage.
  7. Use an oscilloscope to inspect waveform for correct PWM frequency and clean edges. Look for noise, dropouts, or voltage spikes.
  8. If wiring and connector check good but signal still intermittent, substitute or bench-test the pump actuator (if serviceable) or replace injection pump assembly per manufacturer procedure.
  9. If actuator and harness test good, consider PCM output test or reflashing as last resort — confirm with manufacturer diagnostics before replacing PCM.
  10. After repairs, clear codes and road test under conditions similar to freeze frame. Re-scan to confirm code does not return.

Likely causes

  • Corroded/loose connector at fuel metering actuator (most common)
  • Damaged wiring harness where it flexes or routes near moving parts
  • Failing injection pump solenoid/actuator
  • Intermittent ground or low battery voltage during cranking
  • PCM/ECM intermittent output (less common)

Fault status

⚠️ Status
Intermittent fault detected in Injection Pump Fuel Metering Control A circuit. Irregular or missing control signal to the pump metering actuator was observed by the PCM.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours
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Code

P0255

LAND ROVER P — Powertrain

Fuel measurement control of injection pump A - intermittent

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

Causes

  • Damaged or corroded connector at the injection pump fuel metering/actuator
  • Broken, shorted or intermittent wiring (open, short to ground, short to battery) in the control circuit
  • Faulty injection pump metering valve/actuator or internal pump electronics
  • Poor or intermittent ground or battery supply to pump or PCM
  • PCM/ECM software or internal fault
  • Intermittent connection at body harness clips or contact points

Symptoms

  • Malfunction Indicator Lamp (MIL) illumination
  • Hard starting or extended cranking
  • Rough idle, stalling or misfire-like symptoms
  • Reduced engine power or limp-home mode
  • Increased smoke or abnormal exhaust
  • Poor fuel economy or surging under load

What to check

  • Read and record freeze frame data and stored related codes with a scan tool
  • Check for additional fuel-related codes (fuel rail pressure, injectors, pump control)
  • Visually inspect wiring and connectors at the injection pump and PCM for corrosion, damage, or loose pins
  • Backprobe the pump control connector and observe voltage and signal while commanding the actuator with a scan tool
  • Wiggle the harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery voltage and engine grounds for proper connections and continuity

Signal parameters

  • Control type: typically a PWM (pulse-width modulated) command from PCM to pump metering actuator
  • Expected command: variable duty cycle (0–100%) depending on engine load/conditions
  • Connector voltage when commanded ON: near battery voltage; when commanded OFF: low (close to 0 V) or PWM switching
  • Coil/actuator resistance: design-specific — consult vehicle service data; large deviations indicate fault
  • PWM frequency: design-specific (commonly tens to several hundred Hz) — irregular or missing waveform indicates problem

Diagnostic algorithm

  1. Retrieve freeze frame and all stored codes. Note conditions when code set (engine temp, RPM, load).
  2. Visually inspect the pump connector and harness for corrosion, bent pins, chafing, or repairs. Repair any obvious damage before further testing.
  3. Check battery voltage and main engine grounds. Clean and tighten ground points and battery connections as needed.
  4. Backprobe the pump control 'A' connector. With ignition ON and engine OFF, measure voltage at the supply pin and resistance of the actuator if accessible; compare to specs.
  5. With a scan tool, command the fuel metering actuator while monitoring the actual signal. Look for proper response and stable duty cycle. Observe for intermittent loss or erratic duty.
  6. Wiggle/shift harness and connectors while monitoring the live signal to reproduce intermittent behavior. Inspect any cover grommets or flex points for damage.
  7. Use an oscilloscope to inspect waveform for correct PWM frequency and clean edges. Look for noise, dropouts, or voltage spikes.
  8. If wiring and connector check good but signal still intermittent, substitute or bench-test the pump actuator (if serviceable) or replace injection pump assembly per manufacturer procedure.
  9. If actuator and harness test good, consider PCM output test or reflashing as last resort — confirm with manufacturer diagnostics before replacing PCM.
  10. After repairs, clear codes and road test under conditions similar to freeze frame. Re-scan to confirm code does not return.

Likely causes

  • Corroded/loose connector at fuel metering actuator (most common)
  • Damaged wiring harness where it flexes or routes near moving parts
  • Failing injection pump solenoid/actuator
  • Intermittent ground or low battery voltage during cranking
  • PCM/ECM intermittent output (less common)

Fault status

⚠️ Status
Intermittent fault detected in Injection Pump Fuel Metering Control A circuit. Irregular or missing control signal to the pump metering actuator was observed by the PCM.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours
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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