Quadzilla724
4/22/2008 9:13:07 AM
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!!!
EuroGoldLS
4/22/2008 9:50:38 AM
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
4/22/2008 12:29:48 PM
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 code that you may want to take it back to the original shop and give them the info to help them diagnose it.
DTC P1345
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 DTC P1345 will set.
Conditions for Running the DTC
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The engine is running.
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The engine has been running for more than 16 seconds.
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The minimum voltage is 11 volts.
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The variable camphaser is commanded to zero.
Conditions for Setting the DTC The deviation between the crankshaft and the camshaft positions exceeds a calibrated amount.
Action Taken When the DTC Sets
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The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
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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.
Conditions for Clearing the MIL/DTC
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The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
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A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
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A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
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Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Important: Scan tool control of the CMP actuator solenoid is inhibited when DTC P1345 sets. The following conditions may cause this DTC to set:
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An improperly torqued harmonic balancer
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A misbuilt or mis-timed engine
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A loose or missing crank damper bolt
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The camphaser solenoid stuck open
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The camphaser stuck in a position other than 0 degrees
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The camphaser does not return to 0 degrees within 16 seconds
Test Description
The number below refers to the step number on the diagnostic table.
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.
Step Action Values Yes No 1 Did you perform the Diagnostic Go to
Step 2 Go to
Diagnostic System Check - System Check-Engine Controls?
Engine Controls 2 Observe the Freeze Frame/Failure Records for this DTC. Go to Step 3 Go to Diagnostic Aids
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
3 Turn OFF the ignition. Go to Step 8 Go to [link=http://gsi.xw.gm.com/si/showDoc.do?docSyskey=752006&pubCellSyskey=27619&
