P0616

Code

Generic P — Powertrain

Starter Relay A Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 33 EN: 94 RU: 65

AI status

Completed

ready

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Page language: EN

Causes

Short to ground in starter relay control wiring
Failed/shorted starter relay (coil or internal contacts)
Poor or corroded connector or terminal at the relay or PCM
Blown fuse or fusible link supplying the relay
Weak or discharged battery or poor battery connections
Faulty engine/ chassis ground

Symptoms

No-crank (engine does not turn) when key is turned to START
Intermittent starting or starter does not engage consistently
Possible unintended starter engagement while engine is off (rare)
MIL (Check Engine Light) set with P0616 stored
Possible battery drain if relay is stuck closed

What to check

Check battery voltage and terminals (clean and tight)
Read freeze frame and live data with a scan tool to confirm conditions when code set
Visually inspect starter relay, relay socket, wiring harness and connectors for damage or corrosion
Check related fuses and fusible links for continuity
Back-probe the relay control terminal while someone operates the ignition to observe voltage change
Wiggle test harness and connectors while monitoring circuit to reproduce fault

Signal parameters

Battery voltage at rest: ~12.0–12.8 V (higher when charging)
Expected supply to relay coil: battery voltage (~12 V) at all times (fused feed)
Expected relay control signal: typically near 0 V (ground) when PCM activates the relay or near battery voltage when inactive (design-dependent)
Trigger duration: short duration only while key is in START — check for unintended steady activation
If circuit is low-faulting: control wire may read close to 0 V when it should be at battery voltage/float

Diagnostic algorithm

Record code, freeze frame and any related codes; clear code then attempt to reproduce
Verify battery state-of-charge and secure clean battery terminals
Inspect starter relay, socket and wiring for obvious damage or corrosion; repair as needed
Check fuses/fusible links feeding the relay coil; replace if blown
Back-probe the relay coil supply and control terminals. With key in START, confirm supply has battery voltage and control line changes state as expected
If control line is stuck low with relay removed, isolate wiring: disconnect PCM connector and measure control circuit to determine if short to ground remains
If wiring appears OK, swap in a known-good relay to rule out a defective relay
Perform continuity/resistance check from the control terminal to chassis ground and to the PCM driver pin per service manual; compare to specification
If all wiring, grounds and relay check good and PCM does not switch correctly, consider PCM driver fault — confirm with manufacturer procedures before replacing PCM

Likely causes

Starter relay coil shorted internally
Control wire chafed and contacting chassis ground
Corroded relay socket or poor terminal contact
Blown inline fuse feeding the relay coil
Loose/dirty battery negative or engine ground

Fault status

⚠️ Status

P0616 — Starter Relay A Circuit Low. PCM reports low voltage/short-to-ground on starter relay A control circuit; may cause no-crank or intermittent start. Inspect relay, wiring, fuses, grounds, and PCM driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours