OBD-II Code P1004 — What It Means & How to Fix It

What Does This Error Mean?

P1004 means Short Runner Valve Position Malfunction — Out of Range. On engines with a variable intake manifold (also called a short/long runner system), a valve switches between a short intake path at high rpm and a long intake path at low rpm. This improves both power and fuel economy. When the PCM cannot confirm the valve is moving to the correct position, P1004 is set. You may notice a loss of power at certain rpm ranges or a rough idle.

Affected Models

Vehicles with variable-length intake manifold runners
Common in Chrysler, Dodge, and Jeep 2.7L, 3.5L, and 4.0L SOHC V6 engines
Common in Dodge Durango, Chrysler 300, and Jeep Grand Cherokee
Common in some Mitsubishi engines with intake runner control

Common Causes

Failed short runner valve actuator not moving the valve to the commanded position
Broken or cracked short runner valve in the intake manifold
Open or short circuit in the actuator control wiring
Vacuum leak preventing pneumatic actuator from receiving full operating vacuum
Faulty position sensor on the runner valve not confirming position to the PCM

How to Fix It

Check for vacuum leaks first. The short runner valve actuator on many Chrysler engines uses engine vacuum to operate. Listen for hissing near the intake manifold.

A broken vacuum line to the actuator causes the valve to stay in one fixed position and sets P1004.
Locate the short runner valve actuator on the intake manifold. Disconnect the vacuum line and apply vacuum manually with a hand pump.

The actuator should hold vacuum and the valve should move smoothly. A leaking actuator diaphragm cannot hold vacuum.
Inspect the runner valve itself through the intake. Look for broken, stuck, or seized valve plates that cannot rotate to the commanded position.

On high-mileage Chrysler 3.5L engines, the runner valve plates are known to crack and break off into the engine — a serious risk.
Check the actuator electrical connector and wiring for damage. Test voltage and ground at the connector with the key on.

Some vehicles use a mix of vacuum actuation and electrical position sensing. Both need to function for the monitor to pass.
Replace the actuator if it fails the vacuum test. If the valve itself is broken, inspect for loose pieces in the intake before starting the engine.

Broken runner valve pieces ingested into the engine cause catastrophic damage — do not run the engine if pieces are missing.

When to Call a Professional

Actuator replacement typically costs $100 to $350 parts and labor. If the intake manifold runner valve is broken, manifold replacement can cost $400 to $1,200. Vacuum line repair is $50 to $200. Diagnose before replacing the manifold — the actuator is often the only failed part.

Frequently Asked Questions

Can broken runner valve pieces destroy my engine?

Yes — on Chrysler 3.5L engines, the runner valve plates are made of plastic. If they crack and break off, pieces can be ingested into the intake ports. Do not run the engine until you have confirmed all valve pieces are intact.

Will P1004 fail an emissions test?

It depends on your state's rules. P1004 turns on the check engine light, which causes an automatic emissions failure in most states. Fix it before going to emissions inspection.

Does P1004 affect fuel economy?

Yes — the variable runner system is designed to optimize intake flow for both low and high rpm. If the valve is stuck in one position, performance and fuel economy suffer at certain operating conditions.