What it means
The control line for starter relay A is shorted to ground - the ECU drives the relay and measures voltage too low.
At a glance
- Usually lights the check-engine light
How it works
Starter relay A switches the high-current starter circuit when its control module energizes the relay. The module monitors the relay A control line and sets P0616 when its voltage falls below the expected range, consistent with a short to ground.
Common causes
Most likely first.
- Control line shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- No-crank or intermittent starting
How to diagnose it
- Use a scan tool to record freeze-frame data and check whether the fault appears during a start request.
- Inspect starter relay A and its connector for corrosion, loose pins, or heat damage that could interfere with the control signal.
- Trace the relay A control wire for chafing or crushed insulation, especially where the harness passes near metal or other components.
- With the circuit safely isolated as specified by the manufacturer, test the control wire for an unwanted path to ground.
- Check relay operation and the control module's output using the manufacturer's diagnostic procedure before replacing either part.
Common fixes
- Clean and secure corroded or loose relay A connector terminals.
- Repair chafed insulation or a control wire shorted to ground.
- Replace a faulty starter relay A if testing confirms it is defective.
- Repair the control module circuit or replace the module only if its output fails the specified tests.
Can I keep driving?
The engine may fail to crank or start intermittently. Avoid relying on the vehicle until the fault is diagnosed; repeated start attempts can leave you stranded and may drain the battery.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.