OBD-II Generic Error Code P0938: How to Fix It

Q: Can I still drive my car with a P0938 code?

In most cases, you can drive short distances with a P0938 code, but it is not recommended for extended driving or heavy use. The code means your vehicle's hydraulic oil temperature sensor is reporting an out-of-range reading, which could mean the system is genuinely overheating. Continuing to drive with an overheating hydraulic or transmission system risks severe and expensive damage. Have the issue diagnosed as soon as possible.

Q: What vehicles commonly get the P0938 code?

P0938 is most commonly seen in vehicles equipped with continuously variable transmissions (CVTs), such as many Nissan, Honda, Subaru, and Toyota models. It can also appear in vehicles with hydraulic power steering systems, hydraulic clutch systems, or other hydraulically actuated components that use a dedicated temperature sensor. Check your vehicle's service manual to confirm which hydraulic system is monitored by this code on your specific model.

Q: How much does it cost to fix a P0938 error code?

If the fix is simply a faulty hydraulic oil temperature sensor, the sensor itself typically costs between $15 and $80 depending on the vehicle, and labor at a shop can add $50 to $150. If the issue is wiring, repair costs vary widely based on the extent of the damage. If the hydraulic system itself is overheating due to a clogged cooler or transmission damage, repair costs can range from $200 for a cooler flush to $3,000 or more for transmission repairs.

Q: Will a P0938 code cause my car to go into limp mode?

It depends on the vehicle. Some manufacturers program the TCM or ECM to enter a limp or reduced-performance mode when a critical sensor like the hydraulic oil temperature sensor reports out-of-range values, in order to protect the transmission from damage. If your vehicle is stuck in a single gear, has sluggish acceleration, or shows a 'transmission fault' warning light, it may already be in limp mode. Clearing the code and addressing the root cause is the proper solution.

Q: Is P0938 the same as P0710 or P0711?

Not exactly. P0710, P0711, and similar codes (P0712, P0713) relate to transmission fluid temperature sensor faults, while P0938 specifically references the hydraulic oil temperature sensor circuit range or performance. In some vehicles these may monitor the same or similar systems, but they are technically distinct codes. Always diagnose the specific code your vehicle has set, and check your vehicle's service manual to understand exactly which sensor and circuit is being referenced for your make and model.

Abstract

The P0938 error code indicates that your vehicle's hydraulic oil temperature sensor is reading outside of its expected range, meaning the signal from the sensor is either too high, too low, or erratic for normal operating conditions. This code is commonly associated with vehicles that use hydraulic systems — such as those with continuously variable transmissions (CVTs), power steering systems, or hydraulic clutch assemblies — where fluid temperature monitoring is critical. While this is a medium-severity code that won't immediately disable your vehicle, ignoring it can lead to overheating of hydraulic components and costly transmission or steering system damage.