You get into your car to head to work. You turn the key, but instead of roaring to life instantly, the engine cranks and cranks for a solid five seconds. It finally sputters to life, but it idles roughly, and the Check Engine Light pops on immediately.
You plug in your scanner, and it reveals code P0368.
A "long crank" condition combined with a camshaft code usually sends car owners straight to the auto parts store to buy a new sensor. But before you open your wallet, you need to understand exactly what "Circuit High" means. Throwing a new sensor at a broken wire won't fix your car. Let's break down how to accurately diagnose and fix P0368.
What Does Code P0368 Mean?
The technical definition is: "Camshaft Position Sensor 'B' Circuit High (Bank 1)."
Your engine's computer needs to know exactly what position the internal valves are in so it can fire the spark plugs at the perfect microsecond. It gets this information from the Camshaft Position (CMP) Sensor, which reads a spinning toothed wheel attached to the camshaft.
When the computer throws a P0368, it means the electrical signal coming back from the sensor is abnormally high (usually resting at a constant 5 volts or 12 volts, instead of pulsing up and down as the engine turns).
- Sensor "B": This always refers to the Exhaust camshaft sensor (the side pushing exhaust gases out).
- Bank 1: This is the side of the engine block that contains Cylinder #1. (On a standard 4-cylinder engine, there is only one bank).
Top Causes of a "Circuit High" Code
A "Circuit High" almost always points to an electrical fault, not a mechanical timing chain issue. The computer sees maximum voltage because the circuit is broken. The top causes include:
- Unplugged or Loose Connector (Most Common): If you recently had an oil change or engine work done, the mechanic might have bumped the sensor plug. If the plug is loose, the circuit is open, and the computer defaults to reading a "High" voltage.
- Broken Ground Wire: Sensors need a ground to pull the voltage down. If the ground wire leading to the sensor is snapped or corroded, the voltage stays stuck "High".
- Failed CMP Sensor: The internal electromagnet inside the sensor has completely failed, preventing it from generating a pulsing signal.
- Short to Power: The signal wire leading back to the computer has melted and is touching a 12V battery wire, sending a massive voltage spike to the computer.
Work Smarter, Not Harder
You can spend an hour under the hood back-probing wires with a multimeter, or you can let your scanner do the heavy lifting.
Using the iCarsoft CR Pro S, access the Engine Live Data stream and look for "Exhaust Camshaft RPM" or "CMP Sensor B Status." When you crank the engine, you should instantly see the RPM numbers jumping. If the Engine RPM shows 200, but the Camshaft RPM stays at absolutely 0, you have confirmed the computer is totally blind to that sensor. This points directly to a dead sensor or a severed wire harness.
See Live Engine Data with iCarsoftHow to Diagnose and Fix P0368
Step 1: Check the Connector and Wires
Locate Sensor B on Bank 1. Unplug the electrical connector. Look inside for oil saturation (sensors often leak oil internally, ruining the pins) or green corrosion. Tug gently on the three wires leading into the plug; if one stretches like a rubber band, the copper wire inside is broken.
Step 2: Test for Power and Ground
Using a digital multimeter, test the harness plug (with the key in the ON position, engine off). You should find one wire with a 5V reference, one solid ground, and one signal wire. If you don't have a 5V reference or a ground, do not buy a new sensor—your problem is in the wiring harness.
Step 3: Replace the Sensor
If the wiring tests perfectly, the sensor itself has suffered an internal open circuit. Replacing it is very simple: unbolt the 10mm bolt, pull the old sensor out (it might be tight due to the O-ring), push the new one in, and clear the code. Your car should return to starting instantly.
Frequently Asked Questions (FAQ)
Yes, you can usually drive it, but it is not recommended for long periods. The engine computer will enter a "fail-safe" mode, using the Crankshaft sensor to guess the engine timing. This results in the long crank, poor fuel economy, sluggish acceleration, and a rough idle.
When you turn the key, the computer normally looks at the camshaft sensor to determine exactly which cylinder is ready for fuel. Since the sensor is dead (P0368), the computer has to crank the engine several times to mathematically "guess" the timing based on other sensors before it will inject fuel.
If the wiring is good and you only need a new Camshaft Position Sensor, the part usually costs between $30 and $80. It is a very easy DIY fix. If you take it to a repair shop, expect to pay between $150 and $250 for diagnostics, parts, and labor.
