Coolant Pump Control Circuit
Issue with the engine coolant pump control circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine control module is struggling to manage the engine coolant pump, which helps keep the engine from overheating by circulating coolant.
What the computer is actually seeing
The Engine Control Module (ECM) monitors the coolant pump operation and will detect abnormalities like open circuits, shorts, or incorrect voltage signals.
What a healthy reading looks like
Normal operation voltage from the coolant pump should be between 10 to 14 volts, and pump resistance should be approximately 1 to 5 ohms.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors associated with the coolant pump for frays, corrosion, or loose connections. Decision: If damage is found, repair it. Go to step 4. Skipping to step 2 if everything looks good.
- 22. Check the voltage at the coolant pump connector with the engine running. You should see 10-14 volts. Decision: If voltage is out of spec, check the wiring back to the ECM. Move to step 4 if voltage is good.
- 33. Measure the resistance of the coolant pump itself. Expected range is 1-5 ohms. Decision: If resistance is outside of this range, replace the coolant pump. If resistance is good, go to step 4.
- 44. Check for ECM fault codes. If other related codes are present, follow normal diagnostic procedures on those codes. Decision: If only SPN 3370 is present, consider reprogramming the ECM or replacing it as a last resort.
Common causes
- Damaged wiring in the coolant pump circuit
- Faulty coolant pump
- Connector corrosion or poor connection at the pump or ECM
- Failed ECM programming or internal fault
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Can I drive the vehicle with this code?
Yes, but keep an eye on the engine temperature; if it overheats, pull over immediately.
Will this fault code come back after clearing?
It may; if the underlying issue is not fixed, the light will likely return.
Why does this code pair with SPN 3363?
SPN 3363 indicates coolant temperature issues that can relate to pump performance.
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