OBD-II Code P2600 — What It Means & How to Fix It

What it means

P2600 means the ECM detected a low voltage in the circuit controlling the electric auxiliary coolant pump.
This pump circulates coolant independently of the main water pump — it is especially critical for turbocharged vehicles that need coolant flow after shutdown.
A failed pump can cause turbocharger heat soak damage, which is expensive to repair.

Affected Models

All vehicles 1996+ with electric auxiliary coolant pumps
Common in turbocharged vehicles (Ford EcoBoost, VW TSI/TDI)
Common in hybrid and electric vehicles
Common in BMW, Audi, and Mercedes with secondary coolant circuits

Common Causes

Short to ground in the coolant pump control wire
Failed electric coolant pump with an internal short
Damaged pump wiring harness from heat or abrasion
Corroded or loose pump connector
Blown fuse in the coolant pump circuit

How to Fix It

Check the coolant pump fuse — this is the quickest first check.

A blown fuse is the fastest fix and costs almost nothing — always start here before testing the pump or wiring.
Inspect the pump wiring harness near the engine for heat damage or chafing.

The harness often runs close to exhaust components — heat damage causing a short to ground is a very common failure mode.
Test for shorts to ground in the control wire with the pump disconnected.

Disconnecting the pump isolates it from the circuit — if the short disappears, the pump itself has an internal fault.
Check pump motor resistance — a very low reading means an internal short.

A healthy pump motor will show a moderate resistance (typically 1–5 ohms); near-zero ohms confirms an internal winding short.
Replace the electric coolant pump if wiring tests pass and the pump fails resistance checks.

Auxiliary pumps are relatively inexpensive — replacing a confirmed failed pump promptly protects the more expensive turbocharger.

When to Call a Professional

A failed auxiliary coolant pump on a turbocharged vehicle is urgent — the turbo relies on continued coolant flow after the engine shuts off.
A mechanic will check the fuse, test pump resistance, and inspect the wiring before replacing the pump.
Auxiliary coolant pump replacement typically costs $150–$400 including labor.

Frequently Asked Questions

Which vehicles use an electric auxiliary coolant pump?

Turbocharged vehicles commonly use them to cool the turbo bearings after shutdown.
Hybrid and electric vehicles also use them extensively for battery and motor cooling.
Some naturally aspirated engines use them for cabin heater circulation.

Can P2600 cause overheating?

Yes, especially in turbocharged vehicles.
The turbo relies on continued coolant flow after the engine shuts off.
A failed pump allows the turbo to heat-soak, cooking the oil in the bearings and causing premature turbo failure.
Do not ignore this code on a turbocharged vehicle.

How much does an auxiliary coolant pump cost?

Most auxiliary pumps cost $50–$200 for the part alone.
Labor is usually 1–2 hours at a shop rate.
Act promptly — turbocharger damage from heat soak can cost $1,000–$3,000 to repair.