P3438 — Cylinder 5 Exhaust Valve Control Circuit Performance

P3438 — Cylinder 5 Exhaust Valve Control Circuit Performance. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit, poor ground connection.

For Ford vehicles

cylinder 5 exhaust valve control circuit – range/performance problem

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P3438 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the cylinder 5 exhaust valve control for damage, corrosion, chafing or poor contact.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P3438 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P3438 (parts and labor, USD, independent shop rates): Control module repair: $300–$1,000; Replace the faulty sensor or actuator: $150–$500; Repair wiring or connectors: $80–$250. Overall, fixing P3438 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What is the most common cause of P3438?

The most common causes are: corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit, poor ground connection.

Is it safe to drive with P3438?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

What are the symptoms of P3438?

Drivers most often notice: possible limp mode depending on the affected component, increased fuel consumption in some cases, the affected system operates intermittently or not at all, Check Engine Light on.

What does OBD2 code P3438 mean?

How do I diagnose P3438 myself?

Start with a scan: confirm P3438, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the cylinder 5 exhaust valve control, and verify the suspect component against live data before buying parts.

What does P3438 mean?

Seeing P3438 on your scanner? The control unit has caught the sensor and actuator circuits operating outside its calibrated window. The formal description is “Cylinder 5 Exhaust Valve Control Circuit Performance”, and the code is grouped under powertrain (engine/transmission) faults.

P3438 refers specifically to cylinder 5. On inline engines cylinders are counted from the front (belt end); on V-engines the numbering depends on the manufacturer, so check the firing-order diagram for your exact model. Location matters for the repair bill: some cylinders require intake manifold removal, which adds labor time.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with P3438 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

Common symptoms of P3438

possible limp mode depending on the affected component
increased fuel consumption in some cases
the affected system operates intermittently or not at all
Check Engine Light on

What causes P3438?

open or shorted wiring in the circuit
poor ground connection
faulty sensor or actuator of the affected circuit
corroded, loose or damaged connector
control module driver fault

How to diagnose P3438

Connect an OBD2 scanner, confirm P3438 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the cylinder 5 exhaust valve control for damage, corrosion, chafing or poor contact.
Measure reference voltage, ground and signal continuity at the component connector.
Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P3438 does not return.

How to fix P3438

Start with the cheapest and most common causes before replacing expensive parts:

Control module repair — $300–$1,000
Replace the faulty sensor or actuator — $150–$500
Repair wiring or connectors — $80–$250

How much does it cost to fix P3438?

Repair cost depends on which component actually failed. Typical scenarios for P3438 (parts and labor, USD, independent shop rates):

Control module repair: $300–$1,000
Replace the faulty sensor or actuator: $150–$500
Repair wiring or connectors: $80–$250

Overall, fixing P3438 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P3438?