P3438

Code

Generic P — Powertrain

Cylinder 5 Exhaust Valve Control Circuit Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 26 EN: 31 RU: 23

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Page language: EN

Causes

Failed exhaust valve control solenoid/actuator (stuck, electrically open/shorted)
Damaged, corroded or disconnected wiring harness or connector to the actuator
Poor ground or fused/unswitched power supply to the actuator circuit
Oil contamination or internal sticking of the valve actuator/mechanical linkage
Faulty ECM/PCM or driver transistor for the actuator
Blown fuse or faulty relay supplying the actuator circuit

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Reduced engine power or hesitation under load
Rough idle or misfire indicated on scan tool for cylinder 5
Reduced fuel economy and increased exhaust emissions
Possible noise from the valve train or abnormal valve timing behavior
Intermittent faults that may clear after restart

What to check

Read freeze frame and live data with a capable scan tool (command vs actual valve/actuator status, duty cycle, fault readiness)
Visual inspection of wiring and connector at cylinder 5 actuator for damage, corrosion, oil intrusion or loose pins
Check for applicable fuses/relays and verify battery voltage is within spec
Back-probe the actuator connector and measure supply voltage, ground continuity and signal while commanding the actuator
Measure coil/solenoid resistance of the actuator (compare to specification or another cylinder)
Confirm engine oil level/condition; excessive sludge can cause actuator sticking

Signal parameters

Typical supply voltage: battery voltage (approx. 11.5–14.5 V) to the actuator power pin when ignition ON/engine running
Control signal: PWM commanded by ECM; expected frequency often in the 20–200 Hz range (vehicle-specific)
Duty cycle: 0–100% depending on commanded valve position; scan tool should show change when commanded
Actuator coil resistance (typical): commonly 6–30 ohms (vehicle-specific — consult service data)
Open-circuit: infinite resistance; short to ground: near 0 ohms; short to power: near 0 ohms between circuit and battery

Diagnostic algorithm

Connect scan tool, record freeze frame and live data; note whether the ECM is commanding the cylinder 5 exhaust actuator and what actual feedback (if any) is reported.
Perform a visual inspection of connector and wiring at the cylinder 5 actuator. Look for oil, bent pins, corrosion, chafing or broken wires.
Check fuses/relays and verify battery voltage and chassis/engine grounds are good.
Back-probe the actuator connector with ignition ON and while commanding the actuator from the scan tool. Verify battery supply voltage to the power pin and that the ECM provides a switching/grounding signal. Observe PWM frequency and duty change when commanded.
With engine off, isolate and measure actuator coil resistance. Compare to spec or to same actuator on another cylinder. Replace actuator if out of range or intermittent.
If wiring shows open/short or high resistance, perform continuity checks to the ECM and repair/replace wiring or connector as needed.
If actuator and wiring test okay, swap the cylinder 5 actuator with a known-good actuator (if identical) and clear codes. If the code follows the actuator, replace it. If the code stays on cylinder 5, suspect wiring or ECM.
Inspect engine oil condition and perform an oil change if sludge is present; a sticky actuator may be resolved by cleaning or replacement.
If mechanical timing or valve train damage is suspected (related cam/crank codes, compression test failures), perform compression or leak-down test and inspect timing components.
If all else checks good, perform ECM driver circuit testing per manufacturer procedure or replace ECM only after verifying all harness and actuator faults are eliminated.

Likely causes

Failed or electrically intermittent exhaust valve control solenoid/actuator at cylinder 5
Open, short or high-resistance connection in the actuator wiring or connector
Contaminated/sticking actuator due to dirty oil or sludge
Poor ground at actuator or blown fuse feeding the circuit

Fault status

⚠️ Status

Cylinder 5 exhaust valve control circuit performance fault — ECM detected abnormal response from the cylinder 5 exhaust valve actuator/solenoid or its control circuit.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours