Code
P1162
DAEWOO
P — Powertrain
HIGH PRSS PUMP / FUEL LINE MAL
Views:
UK: 3
EN: 4
RU: 11
AI status
Completed
Completed
100%
Causes
- Stuck or failed fuel pressure regulator or relief valve
- Blocked or restricted fuel return line to tank
- Clogged fuel filter or internal line obstruction
- Faulty high-pressure fuel pump delivering excessive pressure
- Defective fuel rail/pressure sensor reporting incorrect high pressure
- Wiring fault or poor connector/ground to fuel pressure sensor or pump control
Symptoms
- Check Engine Light (MIL) illuminated
- Hard starting or no-start condition
- Rough idle, surging, or hesitation under load
- Fuel odor in engine bay or around fuel lines
- Black smoke from exhaust or rich running symptoms
- Reduced fuel economy or poor driveability
What to check
- Read freeze-frame and live data with a capable scan tool (fuel rail pressure, engine speed, load, fuel trims)
- Inspect wiring and connectors at the fuel rail pressure sensor and pump control module for corrosion, damage, or loose pins
- Visually inspect fuel lines for kinks, crimps, damage or signs of leakage
- Check fuel filter condition and service interval; replace if contaminated or restricted
- Measure fuel rail pressure with a calibrated mechanical gauge and compare to specifications at idle and under load
- Inspect the fuel return line to the tank for restrictions, collapsed hose, or blocked check valve
Signal parameters
- Fuel rail pressure (kPa/bar/psi) at idle, part-throttle, and wide-open throttle — compare to OE spec
- Fuel rail pressure sensor voltage (approx. 0.5–4.5 V typical range depending on pressure)
- Sensor frequency or current where applicable (refer to manufacturer data)
- Fuel pump duty cycle or control signal (PWM) from ECM if applicable
- Fuel trim values and commanded fuel injector pulsewidths to evaluate enrichment
Diagnostic algorithm
- Connect scan tool, record freeze-frame data and live fuel rail pressure. Note when fault set (conditions/load).
- Visually inspect wiring and connectors for the fuel pressure sensor and pump control. Repair any damage.
- With key on and engine off, monitor sensor voltage and compare to expected at ambient pressure; a trapped high voltage may indicate sensor or wiring fault.
- Install a calibrated fuel pressure gauge on the fuel rail. Start engine and compare measured pressure to OEM specification at idle and under load.
- If measured pressure is high, isolate cause: temporarily disconnect return line to check for flow/restriction, inspect return hose for collapse, and replace fuel filter if restricted.
- Test fuel pressure regulator/relief valve operation. Replace regulator if it is not venting or relieving pressure properly.
- If mechanical pump overpressure suspected, test/replace high-pressure pump or pump control module per manufacturer procedure.
- If measured pressure is normal but sensor reports high, test sensor signal and ground, backprobe harness, wiggle test while monitoring for intermittent faults. Replace sensor if out of spec.
- Clear codes and road test under conditions that previously set the code to verify repair. Re-scan for reappearance.
- If intermittent or unexplained, consult OEM technical service bulletins and consider ECM or module reflash only after eliminating mechanical and wiring causes.
Likely causes
- Blocked/restricted fuel return or filter causing pressure build-up
- Failed fuel pressure regulator or relief valve stuck closed
- Faulty fuel rail pressure sensor or its wiring producing a false high reading
- High-pressure pump mechanical failure or incorrect installation
Fault status
Status
High pressure detected in fuel pump or fuel line; fuel system overpressure or related sensor/wiring malfunction.
Repair difficulty: Medium
Diagnostic time: 1.5-3 hours
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