P168F

Code

LAND ROVER P — Powertrain

Cold start injection system performance

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 4 EN: 24 RU: 11

AI status

Completed

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Page language: EN

Causes

Faulty cold start injector or solenoid
Open/shorted wiring or poor connector to cold start injector
Faulty injector driver in engine control module (ECM)
Low battery voltage or weak battery during cranking
Faulty engine coolant temperature (ECT) sensor or incorrect temperature reading
Faulty intake air temperature (IAT) sensor or related sensors

Symptoms

Hard starting or extended cranking when engine is cold
Rough idle or misfire after cold start
Increased smoke on cold start (rich condition)
Illuminated check engine light (MIL) with P168F stored
Possible poor drivability until engine reaches normal operating temperature

What to check

Read and record all stored DTCs and freeze-frame data with a diagnostic scanner
Check battery voltage and health; test while cranking
Inspect fuses and relays for the injector/cold start system
Visually inspect cold start injector, harness, and connector for damage or corrosion
Measure resistance of the cold start injector (compare to specification)
Check ECT and IAT sensor readings with scanner during key-on and cold conditions

Signal parameters

Injector coil resistance (cold start injector) — vehicle specific (check service manual)
ECU driver pulse: typically a switched ground or +12V supply during cranking; pulse width varies with temperature
Battery voltage: should remain above ~11V while cranking (manufacturer spec may vary)
ECT sensor voltage/thermistor resistance at known temperatures (cold ambient values)
Fuel rail pressure at cranking (psi/bar) — compare to OEM cold-start spec
Connector pin voltages: supply (12V) and return/driver signal relative to battery ground

Diagnostic algorithm

Connect a capable scan tool, read and record P168F and any other codes; note freeze-frame data (ambient and coolant temps, battery voltage).
Verify battery condition and charging system. Ensure good cranking voltage. Recharge or replace battery if low.
Inspect fuses/relays related to the cold start injector circuit. Replace if blown or faulty.
Visually inspect the cold start injector and connector for damage, corrosion, or contamination. Repair/clean as needed.
With ignition off, disconnect the injector connector. Measure injector coil resistance and compare to OEM spec. Replace injector if out of range.
Turn key to ON (engine off) and measure connector supply pin for +12V (if injector is feed-switched) or check for correct wiring voltages per manual.
Crank engine while monitoring driver/activation signal with a lab scope or multimeter (if applicable). Confirm the ECU is commanding the injector during cold conditions.
If ECU does not command but wiring is intact, trace wiring back to ECU, checking for opens/shorts and good ground connections.
If ECU commands but injector does not operate and wiring is good, replace the cold start injector.
If wiring and injector are good but no proper signal or abnormal signal exists, consider ECU driver fault and consult OEM guidance before replacing ECU.
Verify ECT and IAT sensor readings are plausible for ambient conditions; replace sensors or repair circuits if values are incorrect and affecting cold-start strategy.
After repairs, clear codes, perform cold-start test, and confirm P168F does not return and drivability is restored. Recheck for related codes.

Likely causes

Cold start injector stuck, clogged, or electrically open/shorted
Damaged wiring harness or connector to cold start injector (corrosion, pin damage)
Faulty coolant temperature sensor causing incorrect cold-start strategy
Weak battery/voltage sag during cranking affecting injector operation
Failed injector driver output in the ECU

Fault status

⚠️ Status

P168F — Cold Start Injection System Performance: ECU detected abnormal operation or circuit fault with the cold-start injection system during cold start conditions. Inspect injector, wiring, power/ground, temperature sensors, and ECU driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours

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Manual library for LAND ROVER

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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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