Quadzilla724

I had my 2002 Trailblazer (4.2L 88K mi.) into a technician that works at the independent dealership I purchaced it from. He admits he's a Chrysler-guy and suggested I take my codes to a GM dealer to see if they can suggest a course of action on my problem (at least where to start). I thought I would run it by here first before I began calling around. The symptom is a very rough idle that comes and goes (in strings of days). When it does this, the idle chugs at around 650, rocking the vehicle and the cruise control will not work. This is of course worse when the car is in gear and the brake pedal down. The technician did say the vehicle appears to be running 'rich' from the odor of the exhaust. When accelerating, it hesitates and then goes. Outside of idle it runs fine. He said the things that affect idle (AC, etc) does seem to have any impact.

Anyway, he scanned the code for me and came up with three.

P0128-Coolant Thermostat (Coolant temp below Thermostat termerature)
P0014-Exhaust Camshaft Position Timing over advanced (Bank 1)
P1345-Camshaft to crankshft position correlation fault

A little over a year ago, I did take this in because the CE light was on and would not come off. They did note the P1345 error then, but the truck was running perfectly so nothing was done (they seemed very puzzled by this error).

The technician suspects the P0128 is where to start. Thanks in advance for any insight!!!

EvansBlue

Sounds like the engine timing is off, but on such a new engine thats just silly. Try timing the ignition and see if that clears anything up. I'm assuming it is a distributor-equipped vehicle right?

shawnvw

P0128 shouldn't cause the problems your getting. It simply states that the engine is taking too long to warm up and 99% of the time it needs a new thermostat.
I would be starting with the p1345 code. To answer your question EuroGold, there is no distributor on these engine. Timing is computer controlled. Have you done any recent engine work to the vehicle? There is a current bulletin out on these vehicles that explains how to time the engine properly as its kind of a pain. I'll post a flow chart on the codethat you may want to take it back to the original shop and give them the info to help them diagnose it.



DTC P1345
[/align]
Circuit Description

The powertrain control module (PCM) uses the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor information to monitor the correlation between the crankshaft and camshaft positions. If the deviation between the crankshaft and camshaft position exceeds a calibrated amount DTCP1345 will set.
Conditions for Running the DTC[align=left]
•
The engine is running.[/align][align=left]•
The engine has been running for more than 16seconds.[/align][align=left]•
The minimum voltage is 11volts.[/align][align=left]•
The variable camphaser is commanded to zero.[/align]

Conditions for Setting the DTC

The deviation between the crankshaft and the camshaft positions exceeds a calibrated amount.
Action Taken When the DTC Sets[align=left]•
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.[/align][align=left]•
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.[/align]

Conditions for Clearing the MIL/DTC[align=left]
•
The control module turns OFF the malfunction indicator lamp (MIL) after 3consecutive ignition cycles that the diagnostic runs and does not fail.[/align][align=left]•
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.[/align][align=left]•
A history DTC clears after 40consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.[/align][align=left]•
Clear the MIL and the DTC with a scan tool.[/align]
Diagnostic Aids

Important:Scan tool control of the CMP actuator solenoid is inhibited when DTCP1345 sets.
The following conditions may cause this DTC to set:[align=left]•
An improperly torqued harmonic balancer[/align][align=left]•
A misbuilt or mis-timed engine[/align][align=left]•
A loose or missing crank damper bolt[/align][align=left]•
The camphaser solenoid stuck open[/align][align=left]•
The camphaser stuck in a position other than 0degrees[/align][align=left]•
The camphaser does not return to 0degrees within 16seconds[/align]

Test Description

The number below refers to the step number on the diagnostic table.
[ol]2. If this DTC sets, there is a problem with the camshaft position actuator solenoid high control circuit shorted to voltage or the solenoid stuck open.[/ol]


Step Action Values Yes No


1 Did you perform the Diagnostic Go to Step2 Go to Diagnostic System Check -
System Check-Engine Controls? Engine Controls


2 Observe the Freeze Frame/Failure Records for this DTC. Go to Step3 Go to Diagnostic Aids
Turn OFF the ignition for 30seconds.
Start the engine.
Operate the vehicle within the Conditions for Running
the DTC. You may also operate the vehicle within the
[color=#0000ff] conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?





3 Turn OFF the ignition. Go to Step8Go to [URL=http://gsi.xw.gm.com/si/showDoc.do?docSyskey=752006&pubCellSyskey=2761 9&

EvansBlue

I bow down to the better tech!

goldfish05

those two codes are a normal problem with gm. and if normally if one cant read another it will cause alot of hard start problems and cause that could be going on.

Quadzilla724

Thanks folks. I will pass this along to the tech and see if it helps him. This morning was the worse yet. I normally don't have trouble starting it, but it didn't want to run and really had to give it a lot of gas to keep from dying. After a few minutes, it was idling on its own (but with the original problem).

golfer

P0128 could cause problems if the engine temp sensor and coolant temp sensors don't jive.
The ECM may be confused thinking the engine is cold when it's not and throwing out the too much fuel which may be throwing out the spark and fuel timings.


Just a thought.