OBD-II Code P0616 — What It Means & How to Fix It

What Does This Error Mean?

P0616 means the starter relay control circuit is reading a voltage that is too low. The ECM controls the starter relay by applying or removing voltage on a control wire. When that wire shows lower voltage than expected, P0616 is set. This often means the control wire has a short to ground, or the relay coil is drawing too much current. The car may not crank at all, or may crank inconsistently.

Affected Models

All vehicles 1996+
Common in Ford and Lincoln vehicles
Common in GM cars and trucks
Common in Chrysler, Dodge, and Jeep vehicles
Common in vehicles with electronically controlled starting circuits

Common Causes

Short to ground on the starter relay control wire
Faulty starter relay with a damaged coil that draws excessive current
Damaged wiring between the ECM and the starter relay causing a low signal
Corroded relay connector reducing signal voltage
Faulty ECM output driver for the starter relay circuit

How to Fix It

Unplug the starter relay from the fuse box. With the relay removed, turn the key to Start and measure voltage on the relay's control pin socket in the fuse box. It should read near 12V.

If voltage is low or zero with the relay removed, the problem is in the wiring or the ECM — not the relay.
With the relay removed and the key off, check for voltage on the control wire. Any voltage present when the key is off indicates a wiring short or stuck relay circuit.

This test helps identify shorts that are energizing the circuit when they should not be.
Inspect the control wire from the relay socket back toward the ECM. Look for areas where the wire may have chafed through and is contacting the vehicle body or chassis.

A wire touching metal will short to ground and pull the voltage down.
Plug in a new relay (same type from another slot in the fuse box for testing) and see if the code clears. A relay with a failing coil can cause low voltage on the control circuit.

If swapping the relay clears the code and the car starts normally, replace the original relay.
If wiring and relay are good but the code persists, the ECM's output driver for the relay has failed. Have this confirmed by a shop before replacing the ECM.

ECM output failures are rare. Exhaust all wiring options first.

When to Call a Professional

Wiring and relay repairs are manageable for most DIYers. Starter relays cost $10 to $25 at any auto parts store. Wiring repair at a shop is $75 to $200 depending on damage extent. If the ECM output has failed, ECM replacement is needed — $200 to $600 or more. Always confirm the relay and wiring are bad before suspecting the ECM.

Frequently Asked Questions

What is the difference between P0616 and P0617?

P0616 means the voltage on the starter relay control circuit is too low — usually a short to ground. P0617 means the voltage is too high — usually an open circuit or a wire touching a power source. Both prevent the starter relay from working properly.

Can a bad starter cause P0616?

The starter motor itself does not directly cause P0616. P0616 is about the relay control circuit, not the starter motor itself. However, if a starter motor is drawing extremely high current, it can stress the relay and eventually cause circuit issues.

Is P0616 the same as P0615?

They are related but different. P0615 is a general starter relay circuit malfunction. P0616 specifically identifies low voltage on the control circuit. P0616 gives you more information about the type of fault — pointing more toward a short or low-signal issue.