I have a 2003 gmc envoy and was told the camshaft sensor was bad due to the timing chain starting to go out. The shop has quoted me $1700 to fix the timing chain. This vehicle books out at $5300 and I am not paying them this amount. I have auto experience but I have never done this. I have inquired around and have been told it's easier to pull the motor to do this? Is this correct or is there a easier way to do this?

4.6L V8, DOHC, CHAIN DRIVE CAMS.
NO MILEAGE TOLD AT ALL.
IF THE CHAINS ARE LOOSE YOU GET ERRORS LIKE THAT.
IF NOT LOOSE THE SENSOR IS BAD OR WAS INSTALLED WRONG
OR BAD CHAIN GUIDES
BAD CHAIN DAMPER. (A DYNAMIC HYDRAULIC PART).
THE DAMPERS CAN JAM
NOW YOU KNOW THE WAY , AND YOU GET TO GUESS OR DO THE CHAIN INSPECTIONS

The sensor is located behind the crank pulley mounted to the timing chain cover.

P0017 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)

Symptoms of a P0017 will or may include: Malfunction Indicator Lamp (MIL) illumination The engine may run but with reduced performance The engine may crank but not start The engine may exhibit a rattle near the harmonic balancer indicating the tone ring is damaged The engine may start and run, but poorly Causes Causes may include: Timing chain stretched, or timing belt skipped a tooth due to wear Misalignment of timing belt/chain Tone ring on crankshaft slipped/broken Tone ring on camshaft slipped/broken Bad crank sensor Bad cam sensor Damaged wiring to crank/cam sensor Timing belt/chain tensioner damaged An improperly torqued crankshaft balancer A mis-built or mis-timed engine A loose or missing crankshaft balancer bolt The CMP actuator solenoid stuck open The CMP actuator stuck in a position other than 0 degrees

P0300 Random/Multiple Cylinder Misfire Detected

Symptoms may include: the engine may be harder to start the engine may stumble / stumble, and/or hesitate other symptoms may also be present Causes A code P0300 may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked EGR valve / passages Faulty camshaft position sensor Defective computer

It looks like there are several different areas reporting problems. Lets address the p0014 first, believe it or not you may just need to take it to an oil change facility and have them run a oil flush and have them change the oil and filter with a good quality filter and better than standard conventional oil like a synthetic blend or full synthetic. there is a screen between the magnet and the sensor that will clog and effect the readimg of the sensor. Please do this and have your part store clear the codes and then see what come back before spending any money on dianostics. If the p14 code returns it code be the actuator, timing chain or in a few rare cases as a bad cam or motor. The map senir is an easy fix and easy to install part. the speed sensor and clutch code code just be from a faulty semsor or broken wire thart needs to be tracked

The camshaft sensor is in the distributor, beneath the ignition rotor. The crankshaft sensor is inserted into the passenger side bottom of the timing chain cover. I personally have not seen either of these compnoents cause this type of problem. You probably should take this vehicle to a shop and have them do a diagnostic on it.

The person running the test is an idiot. The OBDII test instrument is not capable of determining if there is a warning lamp failure. It is probably guessing based on voltage level, but lamp resistance does normally vary. The test is supposed to be done visually. Take it to someone else, and they will probably be more competent and pass your car.

Hello
Does the light ever come on while you are driving the vehicle? It is possible that the vehicle does not trigger the code on the key cycle when vehicle is connected to the OBDII scan tool (a cycle is the time from when a vehicle is started to the time the vehicle is turned off) you should however most of the time be able to check a vehicles trouble code history to see what may be turning the light on
Good luck
Chris

What code is popping up fo the service engine light? If you don't have a reader, take it to an Autozone or a place that will read this light for free. Let us know what the code is to help further, as without this, it could be many different things.

The crankshaft position sensor (CKP) and Camshaft position sensor (CMP) work in harmony to control the spark/fuel delivery and timing. They both consist of a reluctor, or tone, ring which passes over a magnetic sensor, which generates a voltage, indicating position.

The crankshaft sensor is part of the primary ignition system and functions as the "trigger". It detects the position of the crankshaft relays that information on to the PCM or the ignition module (depending on the vehicle) to control spark timing. The Camshaft position sensor detects the position of the camshafts and relays the information to the PCM. The PCM uses the CMP signal to identify the beginning of the injector sequence. What ties these two shafts and their sensors together is the timing belt or chain. The cam and crank should be precisely timed together. If the PCM detects that the Crank and Cam signals are out of time by a specific number of degrees, this P0016 code will set.

Symptoms of a P0016 will or may include:
* Malfunction Indicator Lamp (MIL) illumination
* The engine may run but with reduced performance
* The engine may crank but not start
* The engine may exhibit a rattle near the harmonic balancer indicating the tone ring is damaged
* The engine may start and run, but poorly

Causes may include:
* Timing chain stretched, or timing belt skipped a tooth due to wear
* Misalignment of timing belt/chain
* Tone ring on crankshaft slipped/broken
* Tone ring on camshaft slipped/broken
* Bad crank sensor
* Bad cam sensor
* Damaged wiring to crank/cam sensor
* Timing belt/chain tensioner damaged

Possible Solutions:
1. First, visually inspect the cam and crank sensors and their harnesses for damage. If you notice broken/frayed wires, repair and recheck.
2. If you have access to a scope, check the cam and crank patterns. If a pattern is missing, suspect a bad sensor or a slipping tone ring. Remove the cam gear and the crankshaft harmonic balancer and inspect the tone rings for proper alignment and make sure they're not loose or damaged or that they haven't sheared the key that aligns them. If they are properly installed, replace the sensor.
3. If the signal appears normal, then check the timing chain/belt for proper alignment. If it's misaligned, check for a damaged tensioner that may have allowed the chain/belt to slip a tooth or several teeth. Also check that the belt/chain isn't stretched. Repair and recheck.

Other crank sensor codes include P0017, P0018, P0019, P0335, P0336, P0337, P0338, P0339, P0385, P0386, P0387, P0388, and P0389.

Hope helps.

Changing a sensor doesn't stretch a chain.

It needs a CASE learn.