The P0635 OBD2 code is a generic powertrain diagnostic trouble code resulting from the engine control module (ECM) receiving a signal indicating that your vehicle’s power steering control circuit system is experiencing some problems.
Some of the parts of the power steering system that could be the cause of the problem include the ECM, the ABS/TCS module, the power steering motor, the high pressure or low-pressure hoses, or even the line pressure modulator valve.
What’s a P0635 OBD2 code?
This trouble is quite common among OBD-II vehicles from early 1996 and newer, which includes but is not limited to models such as Dodge, Renault, Nissan, Ford, Saturn, and Mercedes.
When the P0635 OBD2 code is at its severity, it can cause tremendous damage as it will shift from being just a check engine light on a car that is operating perfectly well and start developing issues such as a stiff or erratic steering wheel. And as we all know steering problems can cost you so much in terms of safety if they are not given immediate attention.
Error Code P0635: Symptoms, Causes & Fix
Symptoms of the P0635 OBD2 code
The symptoms that are usually associated with a P0635 OBD2 code are:
- A check engine illumination light.
- Noise while steering.
- A stiff or erratic steering wheel.
- Lack of power assists when turning your car’s steering wheel.
- Audible chime
- Loss of hydraulic fluid in the reservoir.
When your car’s Power Control Module (PCM) receives an improper signal from the steering control circuit a P0635 OBD2 code is immediately set followed by the illumination of the check engine light.
Causes of the P0635 OBD2 code
Some of the common causes of the P0635 OBD2 code include:
- A leak in the hydraulic system or insufficient fluid level.
- Blocked or kinked hose.
- Loose-fitting connectors such as a poor cable harness connection, loose bolts, and nuts on the car’s valve assembly.
- Corroded or damaged connector
- Faulty wiring.
- A defective PCM.
- A faulty power steering system
The main purpose of a power steering system is usually to provide the needed voltage to various steering system components. Which in return provides the right fluid pressure within the car’s power steering system to prevent damage to the entire power steering system.
How to diagnose a P0635 OBD2 code and tools needed.
To diagnose the P0635 OBD2 trouble code your automotive mechanic should follow the followings steps:
- First, inspect the power steering fluid level, if it’s below the required level, top it up and then continue with further diagnosis.
- Check out other related components such as the power steering pump pulley, the belt tensioner, the reservoir bag, and the hoses, whether they are in perfect working condition.
- Also, check out for external leaks around the pressure control switch and under the vehicle around the brake fluid reservoir.
- Check the high-pressure hydraulic hoses for any splits that might cause an interior leak.
- Check the voltage level at both ends of the power steering pressure switch and on the PCM.
- Use a scan tool to correct live data when steering the steering wheel and check the pressure that powers the steering control module.
- Look out for low or high pressure within the car’s hydraulic system.
- Reset the diagnostic trouble codes and road test the car for any further problems.
- If all the specs are within the required parameters, look out for any loose cable or connection within the ECM, PCM, the ABS, the power steering control module, and the brake pedal sensor.
Common mistakes to avoid when diagnosing a P0635 OBD2 code
Some of the common mistakes that you or your mechanic should avoid when diagnosing a P0635 OBD2 trouble code include:
- Improper data interpretation of the pressure level around the hydraulic system lines.
- Poor inspection can make it difficult to locate small leaks around your hydraulic system.
- Not utilizing a scan tool to recheck the trouble codes after resetting them.
- Assuming that there is a steering fluid leak without checking the fluid level.
- Inspecting the short circuits and overlooking the open circuits.
How to fix a P0635 OBD2 code?
Depending on the cause of the P0635 OBD2 code several solutions can be used to fix a P0635 OBD2 code such as:
- Replacing the power steering position switch and the pressure switch.
- Cleaning any corrosion from the connectors.
- Repairing or replacing the power steering controller.
- Fixing any hydraulic fluid leak around the power steering controller.
- Replacing or flashing the PCM.
- Repair any kinked or blocked hoses in the brake fluid reservoir.
- Replacing any leaking or damaged high-pressure line.
Tips to follow to avoid a P0635 OBD2 error in the future
Please note that in most instances a P0635 OBD2 code will usually prevent the control module from communicating as it should, which in return triggers other trouble codes in such an occasion, you will need help from a mechanic that is good at what he does as it can be really difficult to pinpoint the problem. Which is likely to result in a misdiagnosis.
Since the P0635 OBD2 code is mainly associated with a power steering issue, in case you start experiencing any kind of stiffness while driving, despite how slight it might be, make sure that you have your car towed for repair. This is because the P0635 OBD2 trouble code can be quite dangerous especially when the cause of the trouble code is a leak in the hydraulic system.
So even if your car is still drivable, do not take the risk as you will be putting your life and that of other road users in grave danger. Hence it’s advisable that once you detect a P0635 OBD2 trouble code make sure that you have it addressed immediately.