Coolant Flow Performance Problem
Indicates an issue with the coolant flow rate in the engine cooling system.
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)
Your engine's computer is seeing that the coolant isn't flowing properly, which can lead to overheating.
What the computer is actually seeing
The engine control module (ECM) compares the actual coolant flow rate to the expected flow rate. If the actual flow is lower than expected, it triggers this code.
What a healthy reading looks like
Coolant temperature should be around 190-220°F (87-104°C); flow rate should meet OEM specifications, typically 1.5-3.5 GPM (gallons per minute).
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.
- 1Check coolant level and top off if low; this is critical. Decision: Is coolant level okay? (Yes: go to step 2; No: fill the system and retest.)
- 2Inspect for obvious leaks or damage to hoses and connections. Decision: Are there leaks? (Yes: repair leaks and retest; No: go to step 3.)
- 3Check the operation of the thermostat using a scan tool to observe coolant temperature. Decision: Is the coolant temperature reading normal? (Yes: go to step 4; No: replace thermostat and retest.)
- 4Test the water pump operation, either visually or by checking flow rate at the heater core. Decision: Is the water pump operational? (Yes: go to step 5; No: replace the pump and retest.)
- 5Run the engine and monitor temperature and flow using a scan tool. Decision: Is the coolant flow within expected range? (Yes: code may require further monitoring; No: investigate further or replace components.)
Common causes
- Clogged coolant passages
- Faulty water pump
- Thermostat stuck closed or open
- Low coolant level
- Blocked radiator
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
You can drive it short distances, but monitor your temperature gauge. Overheating can cause major engine damage.
Will the code come back after repairs?
If you've fixed the underlying issue, it shouldn't return. If it does, another component may be faulty.
Why does this code often appear with P00A6 or P00A7?
Those codes indicate similar coolant flow or temperature issues that can occur together, related to system performance.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →