Code
P0550
GWM
P — Powertrain
- Power steering pressure sensor circuit fault
Views:
UK: 4
EN: 3
RU: 6
AI status
Completed
Completed
100%
Causes
- Open/short in sensor wiring (to ground or battery)
- Poor or corroded connector at the pressure sensor
- Failed power steering pressure sensor
- Blown fuse or loss of reference voltage / ground
- Faulty ECU input or internal module fault
- Intermittent harness damage (chafe, pinched, rodent)
Symptoms
- EPS / power steering warning lamp illuminated
- Reduced or inconsistent steering assist (heavier steering)
- Steering feels erratic or jerky under load
- Possible whining or unusual noise from power steering pump
- DTC P0550 stored; may reappear after clearing
What to check
- Read and record DTC(s) and freeze-frame / live data with a scan tool
- Inspect sensor connector and wiring for corrosion, damage, or loose pins
- Check relevant fuses and power supply circuits for the sensor
- Backprobe sensor connector: verify reference voltage, signal voltage and ground
- Observe live pressure signal while turning the steering wheel and during a test drive
- Wiggle harness and connector while monitoring live data to find intermittent faults
Signal parameters
- Typical sensor type: 2- or 3-wire analog pressure transducer (design varies by model)
- Reference voltage (typical): ~5 V reference (some systems may use vehicle battery voltage); verify exact spec
- Signal voltage (typical expected): approx. 0.5–4.5 V proportional to pressure
- At idle/low steering load: lower signal voltage (near lower end); under heavy steering load: higher voltage (near upper end)
- Check OEM service manual for exact volts/ohms vs pressure curve for the specific GWM model
Diagnostic algorithm
- Verify and record DTC P0550 and any other related codes using a scan tool; check freeze-frame data.
- Visually inspect the power steering pressure sensor, connector, and wiring harness for damage, corrosion, fluid contamination, and secure mounting.
- Check fuses and relays related to power steering / sensor power and confirm battery/ignition supply is present.
- With ignition ON (engine off), backprobe the sensor connector: verify reference voltage, ground continuity, and resting signal voltage. Compare to expected ranges.
- Start engine and monitor live signal while turning the steering wheel (left/right). Signal should change smoothly with steering load; note any dropouts or spikes.
- Perform wiggle/strain test on harness and connector while watching live data to reproduce intermittent faults. Repair any chafed/broken wiring.
- If signal is shorted to 12V or ground, isolate and repair short in harness; if open, repair open circuit or connector.
- If wiring, power and ground are within specification but signal is incorrect, replace the pressure sensor and retest.
- If problem persists after sensor replacement, check ECU input circuit and grounds; consider module testing or replacement per OEM procedure.
- Clear codes and perform a test drive to confirm fault is resolved and P0550 does not return.
Likely causes
- Corroded or loose connector at the pressure sensor
- Broken or shorted wire between sensor and ECU
- Sensor internal failure (stuck or open circuit)
- Blown fuse supplying sensor reference voltage
- Intermittent short when steering rack or hoses move
- ECU/stickered harness splice or poor ground at engine block
Fault status
Status
Power steering pressure sensor circuit fault. ECU detected invalid/absent/out-of-range signal from the PS pressure sensor (P0550).
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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