Code
P0168
Generic
P — Powertrain
Fuel Temperature Too High
Views:
UK: 15
EN: 23
RU: 26
AI status
Completed
Completed
100%
Causes
- Failed or out-of-spec fuel temperature sensor (thermistor)
- Short or high voltage on sensor signal/wiring
- Corroded, loose or damaged connector
- Actual fuel overheating (heat soak, hot fuel return, or fuel heater malfunction)
- PCM/ECM internal fault or software issue
Symptoms
- MIL/Check Engine Light illuminated
- Stored freeze-frame data shows high fuel temperature
- Hard starting, especially after hot soak
- Reduced fuel system performance or limp-home strategy (vehicle-dependent)
- Poor fuel economy or rough idle in some cases
What to check
- Read freeze-frame and live data for fuel temperature and related sensors (ECT, ambient air temp)
- Compare fuel temperature reading with ambient and coolant temperatures
- Visually inspect fuel temp sensor, connector and wiring for damage or corrosion
- Backprobe sensor connector to measure signal voltage and reference ground
- Check for TSBs or software updates for PCM relating to fuel temperature sensing
Signal parameters
- Typical fuel temperature sensor output: about 0.2–4.8 V depending on temperature and sensor type (verify with vehicle-specific data)
- Sensor is usually a thermistor (resistance changes with temperature); expect resistance to change predictably with temperature (consult service manual for values)
- No rapid voltage spikes; signal should be steady or change smoothly with temperature
- Reference circuit and sensor supply voltage present (usually key-on 5 V reference or ground reference depending on design)
Diagnostic algorithm
- Retrieve freeze-frame, freeze parameters and all stored codes. Note vehicle conditions when fault set (engine temp, ambient, fuel pressure).
- Use a scan tool to monitor fuel temperature PID against coolant and ambient temperatures. Confirm reading is abnormally high or erratic.
- Visually inspect sensor and harness for heat damage, kinks, rubbing, pin corrosion, or evidence of fuel leakage at the sensor.
- With key ON engine OFF, backprobe the sensor connector: verify reference voltage (if applicable), signal voltage and ground continuity to PCM. Compare to expected ranges in service data.
- Measure sensor resistance at known fuel temperatures (remove sensor if necessary) and compare to manufacturer resistance vs temperature chart.
- Wiggle harness with live data to look for intermittent changes. Inspect/repair any shorts to battery voltage or abnormal resistance to ground.
- If wiring and sensor check good, inspect fuel routing for heat soak (proximity to exhaust, turbo, or coolant lines) and check for stuck fuel heater elements if fitted.
- If wiring and sensor verified OK, consider ECM input test or reflash/replace ECM as last resort following manufacturer procedures.
- After repairs, clear codes and perform a test drive to confirm code does not return and readings normalize under operating conditions.
Likely causes
- Open or shorted sensor element causing elevated voltage
- Pinched wiring or frayed harness shorted to battery voltage
- Connector corrosion or poor pin contact
- Fuel lines routed too close to heat sources or returning hot fuel from system
- Faulty ECM input stage (less common)
Fault status
Status
Fuel Temperature Too High — PCM detected fuel temperature signal above expected range. MIL on; freeze-frame data stored. Inspect sensor, wiring, and actual fuel temperature before replacing control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0168
LAND ROVER
P — Powertrain
The engine fuel temperature is too high
Views:
UK: 2
EN: 4
RU: 9
AI status
Completed
Completed
100%
Causes
- Failed or out-of-spec fuel temperature sensor (thermistor)
- Short or high voltage on sensor signal/wiring
- Corroded, loose or damaged connector
- Actual fuel overheating (heat soak, hot fuel return, or fuel heater malfunction)
- PCM/ECM internal fault or software issue
Symptoms
- MIL/Check Engine Light illuminated
- Stored freeze-frame data shows high fuel temperature
- Hard starting, especially after hot soak
- Reduced fuel system performance or limp-home strategy (vehicle-dependent)
- Poor fuel economy or rough idle in some cases
What to check
- Read freeze-frame and live data for fuel temperature and related sensors (ECT, ambient air temp)
- Compare fuel temperature reading with ambient and coolant temperatures
- Visually inspect fuel temp sensor, connector and wiring for damage or corrosion
- Backprobe sensor connector to measure signal voltage and reference ground
- Check for TSBs or software updates for PCM relating to fuel temperature sensing
Signal parameters
- Typical fuel temperature sensor output: about 0.2–4.8 V depending on temperature and sensor type (verify with vehicle-specific data)
- Sensor is usually a thermistor (resistance changes with temperature); expect resistance to change predictably with temperature (consult service manual for values)
- No rapid voltage spikes; signal should be steady or change smoothly with temperature
- Reference circuit and sensor supply voltage present (usually key-on 5 V reference or ground reference depending on design)
Diagnostic algorithm
- Retrieve freeze-frame, freeze parameters and all stored codes. Note vehicle conditions when fault set (engine temp, ambient, fuel pressure).
- Use a scan tool to monitor fuel temperature PID against coolant and ambient temperatures. Confirm reading is abnormally high or erratic.
- Visually inspect sensor and harness for heat damage, kinks, rubbing, pin corrosion, or evidence of fuel leakage at the sensor.
- With key ON engine OFF, backprobe the sensor connector: verify reference voltage (if applicable), signal voltage and ground continuity to PCM. Compare to expected ranges in service data.
- Measure sensor resistance at known fuel temperatures (remove sensor if necessary) and compare to manufacturer resistance vs temperature chart.
- Wiggle harness with live data to look for intermittent changes. Inspect/repair any shorts to battery voltage or abnormal resistance to ground.
- If wiring and sensor check good, inspect fuel routing for heat soak (proximity to exhaust, turbo, or coolant lines) and check for stuck fuel heater elements if fitted.
- If wiring and sensor verified OK, consider ECM input test or reflash/replace ECM as last resort following manufacturer procedures.
- After repairs, clear codes and perform a test drive to confirm code does not return and readings normalize under operating conditions.
Likely causes
- Open or shorted sensor element causing elevated voltage
- Pinched wiring or frayed harness shorted to battery voltage
- Connector corrosion or poor pin contact
- Fuel lines routed too close to heat sources or returning hot fuel from system
- Faulty ECM input stage (less common)
Fault status
Status
Fuel Temperature Too High — PCM detected fuel temperature signal above expected range. MIL on; freeze-frame data stored. Inspect sensor, wiring, and actual fuel temperature before replacing control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
