Code
P1025
MITSUBISHI
P — Powertrain
Oil control Valve open(Ex)
Views:
UK: 3
EN: 8
RU: 3
AI status
Completed
Completed
100%
Causes
- Open or broken wiring between ECM and exhaust OCV
- Corroded or loose connector at the OCV
- Failed/externally damaged exhaust OCV (solenoid)
- Blown fuse or faulty power/ground supply to the OCV circuit
- Low engine oil level, severely degraded oil, or clogged oil passages preventing valve response
- ECM internal fault (rare)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated (check engine light)
- Reduced engine performance or torque at some conditions
- Rough idle or hesitation during acceleration
- Engine may run less efficiently (increased fuel consumption)
- Possible abnormal cam timing symptoms (noise, poor throttle response)
What to check
- Scan for related codes and view freeze-frame/fuel/engine conditions when code set
- Visual inspection of OCV connector and wiring for damage, corrosion, pin push-out or water intrusion
- Check engine oil level and condition; top up or change if needed
- Backprobe OCV connector with ignition ON and engine OFF to check for battery power and ground while commanding OCV with a scan tool
- Measure OCV coil resistance and compare to service manual specification
- Use a scan tool to command the OCV on/off and observe PCM feedback, cam timing, or listen/feel for valve activation
Signal parameters
- OCV coil resistance: typically low-ohm coil (check factory spec — commonly single-digit to low-double-digit ohms)
- Connector supply voltage: ~battery voltage (11–14.5 V) with ignition ON (no command)
- Ground: switched by ECM when commanded — measure continuity to engine ground
- Command signal: often PWM duty cycle from ECM; duty varies with engine load/ECM strategy — check scan tool activation and feedback
Diagnostic algorithm
- Retrieve freeze frame data and related camshaft/VVT codes. Note engine oil temp, rpm and load when code stored.
- Perform visual inspection: OCV connector, wiring harness, chafing, corrosion, pin condition and routing to ECM.
- Verify engine oil level and condition; correct if low or contaminated and clear code to see if it returns.
- With ignition ON (engine OFF) backprobe the OCV connector: confirm battery voltage at the power pin and good ground continuity. If no power, inspect fuses/relays and wiring to power source.
- Measure OCV coil resistance with connector disconnected; compare to manufacturer spec. An open or very high resistance indicates a faulty solenoid.
- Command the OCV ON/OFF with a capable scan tool while monitoring voltage/current and listening/feeling for actuation. If commanded but no change and wiring/power good, suspect solenoid or oil feed issue.
- If wiring and power are good but solenoid does not operate, remove and bench-test or substitute a known-good OCV. Replace solenoid if failed.
- If solenoid operates but timing or performance is abnormal, inspect oil passages for clogging and confirm oil pressure to VVT system.
- If all components test good, suspect ECM driver fault; verify with wiring diagram and perform ECM-related checks or replacement only after exhausting external causes.
- Clear codes and perform a road test to verify repair. Re-scan to confirm code does not return.
Likely causes
- Open/broken harness or connector fault at the exhaust OCV (most common)
- Failed exhaust OCV solenoid
- Low oil level or contaminated oil interfering with OCV operation
Fault status
Status
Exhaust oil control valve circuit open — ECM detects open circuit/no current to the exhaust OCV; check wiring, connector, fuse, oil level and the solenoid.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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Code
P1025
RAM
P — Powertrain
WOT Circuit Low
Views:
UK: 0
EN: 5
RU: 1
AI status
Completed
Completed
100%
Causes
- Open or broken wiring between ECM and exhaust OCV
- Corroded or loose connector at the OCV
- Failed/externally damaged exhaust OCV (solenoid)
- Blown fuse or faulty power/ground supply to the OCV circuit
- Low engine oil level, severely degraded oil, or clogged oil passages preventing valve response
- ECM internal fault (rare)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated (check engine light)
- Reduced engine performance or torque at some conditions
- Rough idle or hesitation during acceleration
- Engine may run less efficiently (increased fuel consumption)
- Possible abnormal cam timing symptoms (noise, poor throttle response)
What to check
- Scan for related codes and view freeze-frame/fuel/engine conditions when code set
- Visual inspection of OCV connector and wiring for damage, corrosion, pin push-out or water intrusion
- Check engine oil level and condition; top up or change if needed
- Backprobe OCV connector with ignition ON and engine OFF to check for battery power and ground while commanding OCV with a scan tool
- Measure OCV coil resistance and compare to service manual specification
- Use a scan tool to command the OCV on/off and observe PCM feedback, cam timing, or listen/feel for valve activation
Signal parameters
- OCV coil resistance: typically low-ohm coil (check factory spec — commonly single-digit to low-double-digit ohms)
- Connector supply voltage: ~battery voltage (11–14.5 V) with ignition ON (no command)
- Ground: switched by ECM when commanded — measure continuity to engine ground
- Command signal: often PWM duty cycle from ECM; duty varies with engine load/ECM strategy — check scan tool activation and feedback
Diagnostic algorithm
- Retrieve freeze frame data and related camshaft/VVT codes. Note engine oil temp, rpm and load when code stored.
- Perform visual inspection: OCV connector, wiring harness, chafing, corrosion, pin condition and routing to ECM.
- Verify engine oil level and condition; correct if low or contaminated and clear code to see if it returns.
- With ignition ON (engine OFF) backprobe the OCV connector: confirm battery voltage at the power pin and good ground continuity. If no power, inspect fuses/relays and wiring to power source.
- Measure OCV coil resistance with connector disconnected; compare to manufacturer spec. An open or very high resistance indicates a faulty solenoid.
- Command the OCV ON/OFF with a capable scan tool while monitoring voltage/current and listening/feeling for actuation. If commanded but no change and wiring/power good, suspect solenoid or oil feed issue.
- If wiring and power are good but solenoid does not operate, remove and bench-test or substitute a known-good OCV. Replace solenoid if failed.
- If solenoid operates but timing or performance is abnormal, inspect oil passages for clogging and confirm oil pressure to VVT system.
- If all components test good, suspect ECM driver fault; verify with wiring diagram and perform ECM-related checks or replacement only after exhausting external causes.
- Clear codes and perform a road test to verify repair. Re-scan to confirm code does not return.
Likely causes
- Open/broken harness or connector fault at the exhaust OCV (most common)
- Failed exhaust OCV solenoid
- Low oil level or contaminated oil interfering with OCV operation
Fault status
Status
Exhaust oil control valve circuit open — ECM detects open circuit/no current to the exhaust OCV; check wiring, connector, fuse, oil level and the solenoid.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
Your 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