This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
Crankshaft Position Sensor "A" Circuit Malfunction
This is another trouble code that may require professional assistance depending on the diagnosed root cause. A P0335 code is stored when your vehicle’s powertrain control module (PCM) detects an operational failure in the crankshaft position sensor. The good news is if the PCM detects this problem, it’s probably going to illuminate your Check Engine Light right away. All you need to do is figure out the root cause, then decide if it’s a DIY fix or if it requires a trip to your mechanic.
The list of causes for a P0335 code is fairly brief, but some potential fixes can be complex and expensive. You’ll want to conduct a thorough troubleshooting process step-by-step to find an accurate diagnosis. Here’s where to look first.
- There’s an open circuit or short circuit in the crankshaft position sensor wiring harness.
- Wiring harness connectors are loose or corroded.
- The crankshaft position sensor has failed
- The signal plate is damaged or broken
- You’ve got a busted timing belt or chain
- The PCM itself is damaged or faulty
Let’s talk about how your vehicle is going to let you know there’s a problem. Depending on the manufacturer and model, symptoms may vary significantly for a P0335. The Check Engine Light may light up right away, or it may take a few failed PCM tests before it stores the code. Some vehicles won’t even start up, while others may function poorly and exhibit a drop in engine performance and power. Some drivers may notice a rough idle and stalling. The root cause of the problem will often determine the symptoms, but it’s not a hard and fast rule.
If you’re determined to find the problem and potentially repair it yourself, you need to follow a methodical, step-by-step troubleshooting process. Here’s how to properly diagnose a P0335 trouble code:
Start by pulling all trouble codes with a scan tool, checking for any specifically stored in the PCM. Most vehicles that haven’t been in a shop recently will have current, historical and pending codes stored, and you need to go over your freeze-frame data carefully.
Clear the codes and take the vehicle for a road test. If you can duplicate the symptoms you’ve been experiencing, check the live engine data when the symptoms recur.
Next, make a close visual inspection of the crankshaft position sensor and its wiring harness. Electrical issues are the easiest, least expensive fix, and it is critical to verify that wiring and connectors are not causing this issue before moving on.
After you check the wiring and connectors, use your scan tool to monitor the crankshaft position sensor readings and RPM signal from the PCM. If both of those are within range (check your manufacturer vehicle specs for normal readings), then it’s time to test the wiring connections to and from the position sensor with a multimeter.
Finally, check the PCM itself using the published manufacturer testing protocol (you can generally find this online).
Smart and experienced mechanics make mistakes, too. If it happens to them, it can happen to you. Most DIYers and mechanics start to go wrong when they skip diagnostic steps in the proper order. The most common cause of P0335 trouble code is a faulty crankshaft position sensor and a quick exchange can fix that. Make sure you check out the sensor plate and timing belt or chain, too. Swapping a sensor won’t fix that, and a broken belt/chain and plate can cause serious engine damage if you are driving around with it unrepaired.
How serious is this?
A P0335 code means either a serious mechanical failure or an electrical failure. If the vehicle has problems starting or any driveability issues, don’t drive it until you can take it into a shop.. Some drivers find the vehicle will start once, stall out and then fail to start up again. Additionally, the engine may run poorly for a time and then fail to start up again. Follow the troubleshooting process to find the root cause, or take the vehicle into the shop and verify you don’t have a mechanical issue that could permanently damage your engine and transmission. You are looking at some hefty repair bills if you don’t get everything properly repaired right away.
What repairs can fix the code?
- Swapping out the crankshaft position sensor (moderately expensive and work intensive).
- Repairing/replacing the wiring harness (a quick and inexpensive fix).
- Replacing the PCM (significantly expensive repair)
- Signal plate replaced (fairly inexpensive but labor intensive)
- Repairing or replacing the timing belt/chain (expensive and best left to professionals)
If you are repairing the wiring or sensor, this is an easy fix you can complete yourself. Anything beyond those repairs is going to take some time and experience in repairing or replacing parts in the timing system. Does your diagnostic process indicate the wiring and sensor are fine?
Take your vehicle to a trusted mechanic right away and have them check the timing system. Failing to get a broken belt/chain or major component like the PCM replaced properly is an excellent way to destroy your engine and possibly transmission, too. Don’t be afraid to ask for help if you find yourself in over your head.