P0616
Starter Relay Circuit Low
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The P0616 code is a more specific version of the general P0615 starter relay circuit code. It indicates that the PCM has detected a lower-than-expected voltage in the starter relay circuit. The 'Low' designation tells technicians that the circuit voltage has dropped below the normal operating range, which narrows down the diagnostic direction to issues that cause voltage loss or shorts to ground.
A low voltage reading in the starter relay circuit typically means power isn't getting through properly to engage the starter. You may find that the engine doesn't crank at all, cranks weakly, or only starts intermittently. The check engine light will illuminate, and you may hear clicking from the relay area when you try to start the car — a classic sign that there isn't enough electrical power reaching the starter motor.
Start your diagnosis by checking the battery voltage and ensuring the battery terminals are clean and tight. Then locate the starter relay (usually in the under-hood fuse box) and test or replace it. Carefully inspect all the wiring in the circuit for any signs of chafing, corrosion, or exposed wire that could be shorting to the vehicle's chassis ground. A wiring diagram for your specific vehicle will be very helpful in tracing the circuit. If basic checks don't resolve the issue, a technician with a wiring diagram and multimeter can quickly track down the source of the voltage drop.
Severity
Symptoms
- •Engine fails to crank or cranks very slowly
- •Intermittent no-start condition
- •Clicking sound when attempting to start the vehicle
- •Check engine light illuminated
- •Starter may engage weakly or not at all
Likely Causes
A wire in the starter relay circuit that has chafed through its insulation and contacted a metal ground point will pull the circuit voltage low, triggering the PCM to detect a low voltage condition.
Internal contact degradation in the starter relay can reduce the voltage passed through it, resulting in a low-voltage reading on the output side of the circuit.
Corroded terminals, loose connectors, or degraded wiring in the circuit create excessive resistance that drops the voltage below the PCM's expected threshold.
A battery that cannot maintain adequate voltage under the heavy load of the starter circuit, or corroded battery cables, can cause overall low voltage in the starter relay circuit.
In uncommon cases, the PCM's internal circuit responsible for controlling the starter relay may have an issue, incorrectly reading or producing low voltage on the starter relay control line.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Inspect starter relay circuit wiring for shorts to ground, chafed insulation, or damage
- Replace the starter relay
- Clean corroded battery terminals and cable ends
- Repair or replace damaged wiring connectors in the starter circuit
- Test and replace the battery if it cannot maintain voltage under load