P2602 — Coolant pump electrical circuit voltage too low

The engine's coolant pump is not receiving proper electrical signals, causing it to run improperly or not at all. This can lead to overheating since coolant circulation is affected. The code appears when the control module detects voltage lower than expected in the pump's circuit, indicating a possible wiring or component issue.

Common causes

The cause is almost always one of a few things. Here they are — P2602 rarely comes from anything outside this list:

• Faulty coolant pump motor
• Damaged or corroded wiring/connectors
• Blown fuse or relay in pump circuit
• Faulty control module output
• Poor ground connection

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Check and repair wiring and connectors for damage
2. Test and replace blown fuses or relays
3. Inspect and clean ground connections
4. Test coolant pump operation and replace if faulty
5. Check control module output and repair if needed

That is what holds for P2602 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.