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Error Code P0018 is defined as Crankshaft Position – Camshaft Position Correlation (Bank 2 Sensor A), a generic trouble code that applies to all vehicles, regardless of makes and models. This DTC (diagnostic trouble code) refers to a problem with the vehicle’s camshaft position sensor A for Bank 2, where it doesn’t correlate to the crankshaft position sensor signal.
The CMP or camshaft position sensor, works by determining the position of the crankshaft(s). It then relays the information straight to the PCM (powertrain control module). The PCM will then use the information to control multiple connected components, primarily the fuel injectors and some applications needed for ignition timing. The crankshaft position sensor (CKP) relays the information about the crankshaft position, as well as the engine’s RPM straight to the PCM or even the ignition module. The PCM again, will use this information to control the timing of the ignition as well as to control fuel injection.
This means the crankshaft sensor works as a primary trigger for the vehicle’s ignition system. It detects the crankshaft’s position and then relays the information to the PCM, which then controls the timing of the spark and identifies the beginning of the sequence of the injector. Crankshaft and camshaft, along with their sensors, are tied together through the timing belt or chain. The two should be precisely timed together.
Should the PCM detect an error with the timing on either or both the crank or camshaft, such as the camshaft signal being out of the predetermined range, the error code will show up. It is in Bank 2 where the engine doesn’t have the cylinder number 1, while the ‘A’ sensor works as the intake camshaft side.
Error Code P0018 usually comes with multiple symptoms, such as poor engine performance, hard starting or not starting at all and of course, the illuminated Check Engine light. Some other common symptoms include:
- Engine may start and run, but very poorly
- Normal idle sound, but with significant reduction in acceleration and power
- Engine showing rattle close to the harmonic balancer, suggesting damage to the tone ring
- Decreased fuel mileage
- Engine running erratically, rough riding, or hesitating
Some of the most common causes of Error Code P0018 include:
- Misalignment of chain or timing belt
- Stretched timing chain
- Wear causing timing belt to skip a tooth
- Bad crankshaft or camshaft sensor
- Broken or slipped tone ring on crankshaft or camshaft
- Damage on camshaft or crankshaft’s wiring
- Damaged timing belt or chain tensioner
- Incorrectly torqued crankshaft balancer
- Mis-timed or mis-built engine
- Loose or missing crankshaft balancer bolt
- Stuck open CMP actuator
- Or CMP actuator stuck in 0˚ position
- Problem in VVT
How to Check
Mechanics will usually start to diagnose this error code by checking all the connections and wiring for the camshaft sensors and OCV.
Then, they will check the oil in the engine to make sure it has the correct oil amount and viscosity.
Next, the mechanic will scan the code and check the freeze frame data, and may restart the computer to see if the error code returns. As with other diagnosis for other trouble codes, he will then simulate the freeze frame failure to verify the existence of the code. He may duplicate conditions when the last failure took place.
Then, he will turn on the OCV and turn the bank 2 camshaft off and then check the chamshaft sensor or any changes on the timing.
How to Fix
To fix this problem, technicians have to repair or replace the camshaft sensor on bank 2 wiring. He will look for broken or frayed wires and repair anything that needs repairing.
They have access to the scope, which means they may need to remove the camshaft harmonic balancer as well as the cam gear to check the tone rings, should they suspect a missing pattern, or there’s a problem with the sensor (bad sensor) or slipped tone ring. This should be inspected for proper alignment and make sure they’re neither damaged nor loose.
Repair of the wiring or the camshaft OCV connection.
Replace camshaft OCV or the camshaft sensor for bank 2.
If you own a new vehicle, and it’s still under warranty, then it’s best to have it checked by your dealer.
Different manufacturers may have different specified instructions for this error code. Thus, you can never go wrong on taking the problematic vehicle to the manufacturer or dealer, to help you narrow down the problem.