Code
P2601
Generic
P — Powertrain
Coolant Pump A Control Circuit Performance/Stuck Off
Views:
UK: 17
EN: 62
RU: 39
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring in pump control circuit
- Faulty coolant pump (motor) or internal mechanical seizure
- Failed relay or fuse in pump power feed
- Poor battery/ground connection
- PCM/ECM output driver fault or software issue
Symptoms
- Engine overheating or higher-than-normal coolant temperatures
- Coolant temperature rising after cold start or during load
- Check Engine Light (MIL) illuminated, code P2601 stored
- Reduced HVAC performance if pump affects cabin heating/cooling
- No audible pump operation when expected
What to check
- Scan for DTCs and note freeze-frame and live data when code set
- Visually inspect pump, connector, wiring harness and grounds for damage or corrosion
- Check relevant fuses and relays for continuity and proper operation
- Use a scan tool to command the pump ON and observe PCM command and any change in pump current or RPM
- Measure voltage at pump power and ground pins during commanded ON
- Measure current draw of pump when commanded; compare to expected range or service spec
Signal parameters
- Control signal type: PCM switched ground or PWM control (0–100% duty cycle) depending on vehicle
- Commanded state: ON/OFF and duty cycle from PCM (live data)
- Power supply: ~Battery voltage at power feed when relay/fuse closed
- Ground reference:
- Pump current: should show measurable current when commanded (varies by design; absence of current indicates open circuit or bad pump)
Diagnostic algorithm
- Verify the code with a scan tool. Record freeze-frame and related temps/conditions.
- Inspect harness and connector at the coolant pump for corrosion, bent pins, water intrusion, or physical damage. Repair as needed.
- Check fuses and relays in the pump circuit. Replace any blown fuses and test/replace suspect relays.
- With connector disconnected, measure resistance of the pump motor (bench spec when available). If open or infinite, replace pump.
- Reconnect and back-probe pump power and control pins. Command pump ON with scan tool and observe: battery voltage at power pin, control signal at control pin (PWM or ground switch), and measure current to pump.
- If power present but no pump current, bench-test pump by applying fused battery power to verify operation. If pump runs on direct battery, the harness or PCM control may be at fault.
- If no battery voltage at harness when commanded, trace upstream to relay/fuse and wiring to battery. Repair open/high-resistance circuits.
- If wiring and power are good but pump still does not operate and bench test OK, check PCM control output for proper switching. If PCM output is failed, consider PCM replacement only after confirming wiring and loads are good.
- After repair, clear codes and perform functional test under similar conditions to those that set the code. Monitor live data and verify code does not return.
Likely causes
- Corroded or disconnected pump connector or pin(s)
- Blown fuse or stuck relay supplying pump power
- Pump motor burned out or seized (no current draw when commanded)
- Damaged harness (chafing, high resistance) between PCM and pump
- PCM output transistor failed or intermittent
Fault status
Status
Coolant pump A failed to operate or the control circuit response was outside expected parameters. Inspection of pump, wiring, fuses/relays, and PCM output required.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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