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P0529 OBD-II Trouble Code: Fan Speed Sensor Circuit Intermittent

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P0529 code definition

The P0529 code is a generic powertrain code related to vehicle speed controls and idle control system problems. In this case, the engine control module (ECM) has detected a problem with the fan speed sensor circuit.

Codes related to the P0529 include: * P0480: Cooling Fan 1 Control Circuit * P0481: Cooling Fan 2 Control Circuit * P0482: Cooling Fan 3 Control Circuit * {P0483: Cooling Fan Rationality Check](https://www.yourmechanic.com/article/p0483-obd-ii-trouble-code-cooling-fan-rationality-check-malfunction-by-valerie-johnston) * P0484: Cooling Fan Circuit Over Current * P0485 Cooling Fan Power/Ground Circuit * P0493: Fan Overspeed * P0494: Fan Speed Low * P0495: Fan Speed High * P0526: Fan Speed Sensor Circuit * P0527: Fan Speed Sensor Circuit Range/Performance * P0528: Fan Speed Sensor Circuit No Signal

What the P0529 code means

A P0529 code will appear when the ECM is sent an incorrect voltage signal, in this case an intermittent signal, from the electric cooling fan circuit. If the voltage varies by more than 10% from the manufacturer's preset voltage levels, a P0529 code can be stored.

Some vehicle makes and models have a sensor at the end of the cooling fan, which senses movement when the vehicle is in operation. On a vehicle equipped with an electric fan, this sensor verifies the fan speed detected matches the fan speed commanded by the vehicle’s ECM. The fans usually consist of a primary cooling fan and one or more secondary cooling fans. Most common are single-speed engine cooling fans, but some automakers utilize a fan with multiple speed settings and others utilize an electro-hydraulic cooling fan that uses voltage and hydraulic pressure. It is recommended to check your vehicle service manual for the fan set up and type.

All engine cooling fans are controlled by the ECM, which utilizes the data to calculate fan activation and speed. When the engine reaches a preset temperature (varies by manufacturer and vehicle make/model), the ECM sends a signal to the fan relay. The fan relay has a constant supply of fused voltage and one or more ground signals from the ECM. The cooling fan relay(s) help take the low voltage (or ground) signal and turn it into the signal needed for the cooling fan motor to operate.

What causes the P0529 code?

Several problems may cause a P0529 code including: * Damaged, open, or shorted wiring * Damaged or defective cooling fan motor * Damaged or defective cooling fan relay * Damaged or defective cooling fan speed sensor * Damaged, corroded or loose electrical connectors * Damaged or defective engine coolant temperature sensor * Damaged or defective ECM (rare)

What are the symptoms of the P0529 code?

Symptoms of a P0529 code may include: * The check engine or warning light may illuminate * The vehicle may not display any symptoms other than a stored trouble code * The engine may run hotter than normal * Air conditioner may not work as well, or at all

How does a mechanic diagnose the P0529 code?

A mechanic may use several methods to diagnose a P0529 trouble code, including: * Utilize an OBD-II scanner to check for a stored P0529 trouble code * Visually inspect all wiring and connectors for damage * Utilize a scanner, activate the engine cooling fan, and test for voltage and ground signals * Test system fuses if no voltage is present in engine cooling fan motor * Locate engine fan relay, test voltage readings and compare with manufacturer recommendations * Check and test engine temperature * Test for damaged or defective engine coolant temperature sensor, comparing temperature to manufacturer recommended resistance values * If primary cooling fan isn’t the problem, and secondary cooling fans are present, test secondary cooling fans for damage or faults * Use an RPM to voltage conversion chart to test fan speed

Common mistakes when diagnosing the P0529 code

Often, the cooling fan itself is replaced instead of the wiring, harnesses, or relays. It is recommended to troubleshoot for any electrical issues before replacing the cooling fan.

How serious is the P0529 code?

Because a vehicle’s safe driving operation may be impacted due to faults that store a P0529 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the P0529 code?

Several repairs can fix a P0529 trouble code and include: * Repair any damaged, corroded, shorted, or loose wiring and connectors * Replace damaged or defective engine coolant temperature sensor * Replace damaged or defective cooling fan speed sensor * Repair or replace damaged or defective engine cooling fan motor * Repair or replace damaged or defective engine cooling fan relay * Replace damaged or defective ECM (rare) * Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear

Need help with a P0529 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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