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Home / DTC / P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1

P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1

Detailed page for trouble code P0194.

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22,491specific
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Code

P0194

Generic P — Powertrain

Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1

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

Causes

  • Intermittent/open/short in sensor wiring or connector
  • Corroded, loose or damaged FRP sensor connector/pins
  • Failed or failing fuel rail pressure sensor (intermittent internal fault)
  • Poor sensor reference voltage or ground (intermittent)
  • Intermittent poor battery or charging system voltage
  • Contamination or mechanical issue in fuel rail or regulator causing rapid pressure spikes

Symptoms

  • MIL (Check Engine Light) illuminated, code P0194 stored
  • Intermittent hesitation, stumble or misfire under load
  • Hard start or extended cranking (sometimes)
  • Reduced engine performance or limp-home mode if PCM limits functions
  • Rough idle or stalling in some cases
  • Inconsistent fuel economy

What to check

  • Read freeze-frame and other stored codes; note conditions when P0194 set
  • Monitor live data: FRP sensor voltage/pressure while key on, cranking and running
  • Perform a visual inspection of the FRP sensor connector and wiring for corrosion, damage, pin push-out or water ingress
  • Wiggle test harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery and charging system voltage under load (intermittent low voltage can confuse sensors)
  • Backprobe the sensor connector and verify reference voltage and ground present with key on

Signal parameters

  • Reference voltage: typically 5.0 V ± 0.2–0.3 V (PCM-supplied) at sensor reference pin
  • Sensor ground: near 0 V with good chassis/ECU ground; no intermittent rises when cranking
  • Signal output: many FRP sensors are analog — roughly 0.5 V at low pressure to ~4.5 V at high rail pressure; signal should vary smoothly with throttle/boost
  • During cranking and idle the signal should change smoothly and proportionally to measured fuel pressure; erratic jumps, dropouts to 0 V, or stuck voltage indicate a fault
  • Some vehicles use PWM/digital FRP sensors — expect a stable frequency and duty cycle that changes with pressure; intermittent changes or loss of signal indicate wiring/sensor/ECU issues

Diagnostic algorithm

  1. Retrieve codes and freeze-frame data; note engine conditions when P0194 set
  2. Inspect sensor and harness: visually check connector for corrosion, bent pins, water, or damage; repair or clean as needed
  3. With key ON (engine off) backprobe the connector: verify reference (~5 V), signal, and ground. Do not short pins.
  4. Start engine and monitor live FRP voltage while slowly varying throttle. Observe for smooth change; note any sudden dropouts or spikes.
  5. Wiggle the harness and connector while observing the live signal to try to reproduce the intermittent fault; focus on areas near hot or moving components.
  6. If intermittent is reproduced, isolate the wiring section (repair splice/replace harness) or replace connector/sensor as required.
  7. If no wiring issues found, compare scan-tool FRP reading to a mechanical fuel pressure gauge to confirm real pressure vs sensor output. Relieve fuel pressure before disconnecting or installing gauge.
  8. Use an oscilloscope to inspect the signal for noise, transient spikes, or dropouts (scope is best for intermittent/erratic problems).
  9. If wiring, connector and sensor fail testing, replace the FRP sensor and retest. Clear codes, road test under same conditions to confirm repair.
  10. If new sensor still shows intermittent signal and wiring checks are good, suspect PCM or intermittent ECU power/ground — confirm proper ECU supply/grounds and if necessary consult manufacturer procedures for ECU testing or replacement.

Likely causes

  • Broken or chafed signal wire near engine or harness high-stress area
  • Corroded terminal or water intrusion at sensor connector
  • Sensor internal intermittent element (wear/failure)
  • Loose ground or fractured ground strap near fuel rail/engine
  • Intermittent short to battery or ignition feed affecting 5V reference
  • Fuel pressure regulator or pump producing unstable pressure spikes that the sensor reports

Fault status

⚠️ Status
P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1: PCM detected an unstable/erratic signal from the Bank 1 fuel rail pressure sensor. The fault is intermittent, indicating the signal circuit or sensor output was unreliable long enough to set the code.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-3.0 hours

Similar codes

P0190 P0191 P0192 P0193 P0195 P0087
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Code

P0194

GWM P — Powertrain

- Fuel temperature sensor fault

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

Causes

  • Intermittent/open/short in sensor wiring or connector
  • Corroded, loose or damaged FRP sensor connector/pins
  • Failed or failing fuel rail pressure sensor (intermittent internal fault)
  • Poor sensor reference voltage or ground (intermittent)
  • Intermittent poor battery or charging system voltage
  • Contamination or mechanical issue in fuel rail or regulator causing rapid pressure spikes

Symptoms

  • MIL (Check Engine Light) illuminated, code P0194 stored
  • Intermittent hesitation, stumble or misfire under load
  • Hard start or extended cranking (sometimes)
  • Reduced engine performance or limp-home mode if PCM limits functions
  • Rough idle or stalling in some cases
  • Inconsistent fuel economy

What to check

  • Read freeze-frame and other stored codes; note conditions when P0194 set
  • Monitor live data: FRP sensor voltage/pressure while key on, cranking and running
  • Perform a visual inspection of the FRP sensor connector and wiring for corrosion, damage, pin push-out or water ingress
  • Wiggle test harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery and charging system voltage under load (intermittent low voltage can confuse sensors)
  • Backprobe the sensor connector and verify reference voltage and ground present with key on

Signal parameters

  • Reference voltage: typically 5.0 V ± 0.2–0.3 V (PCM-supplied) at sensor reference pin
  • Sensor ground: near 0 V with good chassis/ECU ground; no intermittent rises when cranking
  • Signal output: many FRP sensors are analog — roughly 0.5 V at low pressure to ~4.5 V at high rail pressure; signal should vary smoothly with throttle/boost
  • During cranking and idle the signal should change smoothly and proportionally to measured fuel pressure; erratic jumps, dropouts to 0 V, or stuck voltage indicate a fault
  • Some vehicles use PWM/digital FRP sensors — expect a stable frequency and duty cycle that changes with pressure; intermittent changes or loss of signal indicate wiring/sensor/ECU issues

Diagnostic algorithm

  1. Retrieve codes and freeze-frame data; note engine conditions when P0194 set
  2. Inspect sensor and harness: visually check connector for corrosion, bent pins, water, or damage; repair or clean as needed
  3. With key ON (engine off) backprobe the connector: verify reference (~5 V), signal, and ground. Do not short pins.
  4. Start engine and monitor live FRP voltage while slowly varying throttle. Observe for smooth change; note any sudden dropouts or spikes.
  5. Wiggle the harness and connector while observing the live signal to try to reproduce the intermittent fault; focus on areas near hot or moving components.
  6. If intermittent is reproduced, isolate the wiring section (repair splice/replace harness) or replace connector/sensor as required.
  7. If no wiring issues found, compare scan-tool FRP reading to a mechanical fuel pressure gauge to confirm real pressure vs sensor output. Relieve fuel pressure before disconnecting or installing gauge.
  8. Use an oscilloscope to inspect the signal for noise, transient spikes, or dropouts (scope is best for intermittent/erratic problems).
  9. If wiring, connector and sensor fail testing, replace the FRP sensor and retest. Clear codes, road test under same conditions to confirm repair.
  10. If new sensor still shows intermittent signal and wiring checks are good, suspect PCM or intermittent ECU power/ground — confirm proper ECU supply/grounds and if necessary consult manufacturer procedures for ECU testing or replacement.

Likely causes

  • Broken or chafed signal wire near engine or harness high-stress area
  • Corroded terminal or water intrusion at sensor connector
  • Sensor internal intermittent element (wear/failure)
  • Loose ground or fractured ground strap near fuel rail/engine
  • Intermittent short to battery or ignition feed affecting 5V reference
  • Fuel pressure regulator or pump producing unstable pressure spikes that the sensor reports

Fault status

⚠️ Status
P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1: PCM detected an unstable/erratic signal from the Bank 1 fuel rail pressure sensor. The fault is intermittent, indicating the signal circuit or sensor output was unreliable long enough to set the code.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-3.0 hours

Similar codes

P0190 P0191 P0192 P0193 P0195 P0087
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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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Code

P0194

HUMMER P — Powertrain

Fuel Rail Pressure Sensor Circuit Intermittent

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

Causes

  • Intermittent/open/short in sensor wiring or connector
  • Corroded, loose or damaged FRP sensor connector/pins
  • Failed or failing fuel rail pressure sensor (intermittent internal fault)
  • Poor sensor reference voltage or ground (intermittent)
  • Intermittent poor battery or charging system voltage
  • Contamination or mechanical issue in fuel rail or regulator causing rapid pressure spikes

Symptoms

  • MIL (Check Engine Light) illuminated, code P0194 stored
  • Intermittent hesitation, stumble or misfire under load
  • Hard start or extended cranking (sometimes)
  • Reduced engine performance or limp-home mode if PCM limits functions
  • Rough idle or stalling in some cases
  • Inconsistent fuel economy

What to check

  • Read freeze-frame and other stored codes; note conditions when P0194 set
  • Monitor live data: FRP sensor voltage/pressure while key on, cranking and running
  • Perform a visual inspection of the FRP sensor connector and wiring for corrosion, damage, pin push-out or water ingress
  • Wiggle test harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery and charging system voltage under load (intermittent low voltage can confuse sensors)
  • Backprobe the sensor connector and verify reference voltage and ground present with key on

Signal parameters

  • Reference voltage: typically 5.0 V ± 0.2–0.3 V (PCM-supplied) at sensor reference pin
  • Sensor ground: near 0 V with good chassis/ECU ground; no intermittent rises when cranking
  • Signal output: many FRP sensors are analog — roughly 0.5 V at low pressure to ~4.5 V at high rail pressure; signal should vary smoothly with throttle/boost
  • During cranking and idle the signal should change smoothly and proportionally to measured fuel pressure; erratic jumps, dropouts to 0 V, or stuck voltage indicate a fault
  • Some vehicles use PWM/digital FRP sensors — expect a stable frequency and duty cycle that changes with pressure; intermittent changes or loss of signal indicate wiring/sensor/ECU issues

Diagnostic algorithm

  1. Retrieve codes and freeze-frame data; note engine conditions when P0194 set
  2. Inspect sensor and harness: visually check connector for corrosion, bent pins, water, or damage; repair or clean as needed
  3. With key ON (engine off) backprobe the connector: verify reference (~5 V), signal, and ground. Do not short pins.
  4. Start engine and monitor live FRP voltage while slowly varying throttle. Observe for smooth change; note any sudden dropouts or spikes.
  5. Wiggle the harness and connector while observing the live signal to try to reproduce the intermittent fault; focus on areas near hot or moving components.
  6. If intermittent is reproduced, isolate the wiring section (repair splice/replace harness) or replace connector/sensor as required.
  7. If no wiring issues found, compare scan-tool FRP reading to a mechanical fuel pressure gauge to confirm real pressure vs sensor output. Relieve fuel pressure before disconnecting or installing gauge.
  8. Use an oscilloscope to inspect the signal for noise, transient spikes, or dropouts (scope is best for intermittent/erratic problems).
  9. If wiring, connector and sensor fail testing, replace the FRP sensor and retest. Clear codes, road test under same conditions to confirm repair.
  10. If new sensor still shows intermittent signal and wiring checks are good, suspect PCM or intermittent ECU power/ground — confirm proper ECU supply/grounds and if necessary consult manufacturer procedures for ECU testing or replacement.

Likely causes

  • Broken or chafed signal wire near engine or harness high-stress area
  • Corroded terminal or water intrusion at sensor connector
  • Sensor internal intermittent element (wear/failure)
  • Loose ground or fractured ground strap near fuel rail/engine
  • Intermittent short to battery or ignition feed affecting 5V reference
  • Fuel pressure regulator or pump producing unstable pressure spikes that the sensor reports

Fault status

⚠️ Status
P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1: PCM detected an unstable/erratic signal from the Bank 1 fuel rail pressure sensor. The fault is intermittent, indicating the signal circuit or sensor output was unreliable long enough to set the code.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-3.0 hours

Similar codes

P0190 P0191 P0192 P0193 P0195 P0087
Repair manuals

Manual library for HUMMER

138

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Code

P0194

LAND ROVER P — Powertrain

Intermittent fuel rail pressure sensor circuit

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

Causes

  • Intermittent/open/short in sensor wiring or connector
  • Corroded, loose or damaged FRP sensor connector/pins
  • Failed or failing fuel rail pressure sensor (intermittent internal fault)
  • Poor sensor reference voltage or ground (intermittent)
  • Intermittent poor battery or charging system voltage
  • Contamination or mechanical issue in fuel rail or regulator causing rapid pressure spikes

Symptoms

  • MIL (Check Engine Light) illuminated, code P0194 stored
  • Intermittent hesitation, stumble or misfire under load
  • Hard start or extended cranking (sometimes)
  • Reduced engine performance or limp-home mode if PCM limits functions
  • Rough idle or stalling in some cases
  • Inconsistent fuel economy

What to check

  • Read freeze-frame and other stored codes; note conditions when P0194 set
  • Monitor live data: FRP sensor voltage/pressure while key on, cranking and running
  • Perform a visual inspection of the FRP sensor connector and wiring for corrosion, damage, pin push-out or water ingress
  • Wiggle test harness and connector while monitoring live data to reproduce intermittent behavior
  • Check battery and charging system voltage under load (intermittent low voltage can confuse sensors)
  • Backprobe the sensor connector and verify reference voltage and ground present with key on

Signal parameters

  • Reference voltage: typically 5.0 V ± 0.2–0.3 V (PCM-supplied) at sensor reference pin
  • Sensor ground: near 0 V with good chassis/ECU ground; no intermittent rises when cranking
  • Signal output: many FRP sensors are analog — roughly 0.5 V at low pressure to ~4.5 V at high rail pressure; signal should vary smoothly with throttle/boost
  • During cranking and idle the signal should change smoothly and proportionally to measured fuel pressure; erratic jumps, dropouts to 0 V, or stuck voltage indicate a fault
  • Some vehicles use PWM/digital FRP sensors — expect a stable frequency and duty cycle that changes with pressure; intermittent changes or loss of signal indicate wiring/sensor/ECU issues

Diagnostic algorithm

  1. Retrieve codes and freeze-frame data; note engine conditions when P0194 set
  2. Inspect sensor and harness: visually check connector for corrosion, bent pins, water, or damage; repair or clean as needed
  3. With key ON (engine off) backprobe the connector: verify reference (~5 V), signal, and ground. Do not short pins.
  4. Start engine and monitor live FRP voltage while slowly varying throttle. Observe for smooth change; note any sudden dropouts or spikes.
  5. Wiggle the harness and connector while observing the live signal to try to reproduce the intermittent fault; focus on areas near hot or moving components.
  6. If intermittent is reproduced, isolate the wiring section (repair splice/replace harness) or replace connector/sensor as required.
  7. If no wiring issues found, compare scan-tool FRP reading to a mechanical fuel pressure gauge to confirm real pressure vs sensor output. Relieve fuel pressure before disconnecting or installing gauge.
  8. Use an oscilloscope to inspect the signal for noise, transient spikes, or dropouts (scope is best for intermittent/erratic problems).
  9. If wiring, connector and sensor fail testing, replace the FRP sensor and retest. Clear codes, road test under same conditions to confirm repair.
  10. If new sensor still shows intermittent signal and wiring checks are good, suspect PCM or intermittent ECU power/ground — confirm proper ECU supply/grounds and if necessary consult manufacturer procedures for ECU testing or replacement.

Likely causes

  • Broken or chafed signal wire near engine or harness high-stress area
  • Corroded terminal or water intrusion at sensor connector
  • Sensor internal intermittent element (wear/failure)
  • Loose ground or fractured ground strap near fuel rail/engine
  • Intermittent short to battery or ignition feed affecting 5V reference
  • Fuel pressure regulator or pump producing unstable pressure spikes that the sensor reports

Fault status

⚠️ Status
P0194 — Fuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 1: PCM detected an unstable/erratic signal from the Bank 1 fuel rail pressure sensor. The fault is intermittent, indicating the signal circuit or sensor output was unreliable long enough to set the code.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-3.0 hours

Similar codes

P0190 P0191 P0192 P0193 P0195 P0087
320

Browse 320 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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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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