Yesterday I had a CEL. The code was a P340 which is a cam sensor. I haven't installed a new sensor yet..I can clear the code with my Scan Gage and it will stay out for a while, then come back in. When I put the vehicle in gear at idle I hear a ting ting sound, take it out of gear no sound. I think that either something is loose or broken in the cam chain area. ANY IDEAS?? I think this could get expensive at a dealer but I don't want to "easter egg" it at a shade tree shop. If I was home I would go into it myself, but I'm at a job 700 miles from my home.

 

Can you locate where the tinging is coming from? It sounds as if the tensioners on your chain may not be working. Or the chain itself is stretched pass the point where the tensioners can work. If the sound is coming from behind the timing chain cover, I'd be very careful about running the engine. If the chain slips, you could smash the valves into the pistons.

 

I can't speculate on your problem, but hopefully some of the following will help you out.

Camshaft Position Sensor

The camshaft position (CMP) sensor detects the position of the camshaft. The CMP sensor identifies when piston No. 1 is on its compression stroke. A signal is then sent to the powertrain control module (PCM) and used for synchronizing the firing of sequential fuel injectors. The Coil On Plug (COP) Ignition applications also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit.

The Variable Cam Timing System allows the exhaust cam to advance and retard at varying engine speeds. The purpose of this is to reduce exhaust emissions and increase fuel economy. As the exhaust cam retards in relation to the crankshaft position, residual exhaust gases are left in the combustion chamber. The residual gases cool the combustion chamber and are inert when mixed with the incoming fresh charge of fuel and air. This results in better fuel economy and lower nitrogen oxides (NOx) and hydrocarbons (HC) the engine produces.
Variable Cam Timing

The Variable Cam Timing (VCT) System consists of the control solenoid, five-tooth pulse ring (4+1) on exhaust camshaft, intake air temperature (IAT) sensor, engine coolant temperature (ECT) sensor, camshaft position (CMP) sensor, mass air flow (MAF) sensor, crankshaft position (CKP) sensor, powertrain control module (PCM).

1. The powertrain control module (PCM) receives input signals from the intake air temperature (IAT) sensor, engine coolant temperature (ECT) sensor, camshaft position (CMP) sensor, mass air flow (MAF) sensor and crankshaft position (CKP) sensor for determining the operating conditions of the engine.

2. The Variable Cam Timing (VCT) system is enabled by the PCM when the proper conditions are met. The PCM disables the VCT system if a fault is detected.

3. The PCM calculates relative cam position using the CMP sensor and data from the (4+1) pulse ring mounted on the exhaust camshaft. Relative cam position is calculated by measuring the time between the rising edge of profile ignition pickup (PIP) and the falling edge of VCT pulse.

4. The PCM continually calculates a cam position error value based on the difference between the desired and actual position and a duty cycle is commanded for the VCT solenoid valve. Engine oil is allowed to flow to the VCT unit.

5. Oil flows to either side of the piston chamber changing a linear motion from the piston to a rotation motion from the helical mechanism in the VCT unit. During closed loop the PCM outputs a revised duty cycle to the VCT solenoid valve to correct for cam position error.

Hardware

Variable Cam Timing (VCT) Solenoid Valve

The VCT solenoid valve is an integral part of the VCT system. The solenoid valve controls the flow of engine oil to the variable cam timing unit assembly. As the PCM duty cycles the solenoid valve, oil is allowed to flow to the VCT unit assembly and advance or retard the cam timing.


Variable Cam Timing (VCT) Unit Assembly

The variable cam timing unit assembly is coupled to the camshaft through a helical spline in the VCT unit chamber. When the flow of oil is shifted from one side of the chamber to the other, the differential change in oil pressure forces the piston to move linearly along the axis of the camshaft. This linear motion is translated into rotational camshaft motion through the helical spline coupling. A spring installed in the chamber is designed to hold the camshaft in the minimum overlap position (5 degrees) when oil pressure is too low to maintain adequate position control. The camshaft is allowed to rotate up to 30 degrees.

 

Well I took it to the local Stealership. Their bill was 145.00. The rental car was 39.00, only drove 10 miles. They replaced the Cam Position Sensor that I PROVIDED for $45.00, the rate for a half our, the other was the diagnostic charge. They said they couldn't find ANYTHING wrong. I sure do hope they are right. I"m away from home and didn't have the time to check out an independent "fix it" shop. OH WELL

 

I still have the ting ting sound but only when it is in gear. I can hear it when going past a security check point and getting into my parking space at the apartment. Could something in the transmission cause the tinny sound, like maybe the torque converter. The CEL has not come on since the cam censor was replaced.

 

You are going to need to narrow down where the noise is coming from. Can you have somebody put the truck in gear and hold the brake while you walk around the truck? Try a mechanics stethoscope on the front cover and see if you can hear it there.

 

Belt tensioner?

Does it go away if you turn off the A/C?