Code
P1020
MITSUBISHI
P — Powertrain
Oil control valve
Views:
UK: 9
EN: 11
RU: 6
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring in the OCV circuit
- Poor or corroded connector contact at the OCV
- Stuck or mechanically seized oil control valve (solenoid)
- Low engine oil level, dirty oil, or oil contamination
- Faulty oil control valve (solenoid)
- Faulty ECM or driver transistor (less common)
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light on
- Reduced engine performance or hesitation
- Rough idle or stalling in some cases
- Poor fuel economy
- Abnormal or increased engine noise at certain RPMs
- Possible limp-home or reduced power mode
What to check
- Read freeze frame and live data with a scan tool; note OCV duty cycle, commanded position, and related cam/crank data
- Visual inspection of OCV connector and harness for damage, corrosion, or oil contamination
- Check engine oil level, condition and service history
- Measure OCV coil resistance with a multimeter and compare to spec
- Backprobe harness to measure supply voltage and ground while operating (use care)
- Check for stored related cam/crank position codes or oil pressure codes
Signal parameters
- Typical coil resistance: commonly in the range ~6–30 ohms (varies by engine) — compare to factory spec
- Supply voltage to OCV: battery voltage (~12 V) on power feed
- Control signal: PWM from ECM; duty cycle varies from 0% to ~100% depending on commanded position
- Control frequency: typically tens to several hundred Hz depending on manufacturer
- Expected behavior: coil has continuity, PWM duty changes with commanded timing; no short to battery or ground
Diagnostic algorithm
- Verify code and capture freeze-frame and live data. Note when the fault occurs (cold/hot, RPM/load).
- Inspect the OCV connector and wiring for damage, corrosion, oil intrusion or loose pins. Repair any visible damage.
- Check engine oil level and condition. If oil is low or heavily contaminated, correct level and perform oil change before further testing.
- With ignition off, measure OCV coil resistance at the connector. Compare to factory specification. Replace OCV if out of range.
- With key on (engine off) and backprobing, verify constant power feed and good ground to the connector. If supply/ground missing, trace and repair wiring.
- Start engine and monitor OCV control signal with a scope or scan tool. Confirm ECM commands (duty cycle) and that the solenoid responds (current draw changes).
- If wiring and connector are good but OCV does not respond, remove and bench-test the solenoid by applying battery voltage briefly (observe valve movement). Replace if stuck or inoperative.
- If solenoid and wiring test good, check continuity and resistance between the OCV and ECM driver pin. Inspect ECM grounds and related fuses/relays.
- If wiring and OCV are good and ECM does not drive correctly, consider ECM driver failure and consult manufacturer procedures for ECM testing/replacement.
- After repairs, clear codes and perform a road test to confirm the fault does not return. Re-scan for related codes and verify normal operation.
Likely causes
- Contaminated or oxidized connector/wiring causing intermittent connection
- OCV coil resistance outside specification (internal fault)
- Mechanical sticking of the valve due to varnish or debris in oil passages
- Low oil pressure preventing proper valve operation
- ECM driver failure on the control channel
Fault status
Status
Stored when the engine control module detects an abnormal condition in the oil control valve circuit or the valve itself (open, short, stuck, or improper response).
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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