P0691 on Chevrolet: How to Diagnose & Fix
Fan 1 Control Circuit Low
1 Chevrolet model · 1 documented issue · 1 critical
P0691 on Chevrolet by model: symptoms, diagnosis and fix
GM says water can migrate along the forward lamp wiring harness into the cooling fan connector on some 2016 Camaros, causing lost connection and terminal corrosion; the Check Engine light can come on, and if the loss of fan operation is not corrected the engine can overheat or be damaged. Owners of 2017-2018 V6 cars also report overheating at idle and a cooling fan that only runs after being tapped. Applies to: 2016 Camaro with the 3.6L V6 (LGX) or 2.0L turbo (LTG), per GM Customer Satisfaction Program N152026170; 2017-2018 Camaro with the 3.6L V6, per the owner reports linked here.
How to Fix
If the temperature gauge climbs at idle or the fan does not run when hot, have a technician check the cooling fan, its connector and wiring. For 2016 cars, GM's program N152026170 had dealers inspect the connector and ground terminals for water or corrosion, clean and seal them, or replace the wiring harness and/or cooling fan module if necessary; that program ended on June 30, 2018. The 2017-2018 reports are summarized from the owner reports linked here; not a manufacturer finding. Your vehicle's equipment and history may differ; a technician must confirm the cause.
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Sources for this issue (3)
P0691 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0691 mean on a Chevrolet?
P0691 stands for "Fan 1 Control Circuit Low." This code means the engine computer detected low voltage (or a short to ground) in the control circuit for cooling fan 1. The PCM commands the cooling fan via a relay or control circuit and monitors the signal voltage. A fault can prevent the fan from running properly, risking engine overheating in traffic or at low speeds. On Chevrolet it is documented across 1 model: Camaro.
What are the most common causes of P0691?
The most common causes of P0691 are: Faulty cooling fan relay, Failed cooling fan motor, Short to ground in the fan control wiring, Corroded or damaged fan connector, Blown fan fuse, PCM fan-control driver fault. The specific cause varies by vehicle.
How much does it cost to fix P0691 on a Chevrolet?
Repair costs vary widely with the root cause and Chevrolet model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.