P0302,& P0380

DTC P0301-P0308
Circuit Description
The engine control module (ECM) monitors changes in crankshaft speed using inputs from the crankshaft position (CKP) sensor and the fuel injection control module (FICM). The ECM adjusts the fuel delivery to each cylinder in order to minimize crankshaft speed changes. This diagnostic trouble code (DTC) will set when the ECM identifies a cylinder or cylinders requiring an excessive amount of fuel in order to maintain the correct crankshaft speed.

Conditions for Running the DTC
The engine is running at idle for more than 90 seconds.
The engine coolant temperature (ECT) is more than 56°C (132°F).
Conditions for Setting the DTC
The fuel rate adjustment for a cylinder exceeds an acceptable value.

Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
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
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
A misfire with no other DTC's will be caused by an engine mechanical or fuel injector problem.

DTC P0380 (Federal RPO FE9, NG1)
Circuit Description
The glow plug system is used to assist in providing the heat required to begin combustion during cold engine temperatures. The glow plugs are heated before and during cranking, as well as initial engine operation. The engine control module (ECM) controls the glow plug ON times by monitoring coolant temperature and glow plug voltage.

Conditions for Running the DTC
The ignition switch in the ON position.

Conditions for Setting the DTC
The ECM has commanded glow plugs ON and the glow plug signal voltage is less than 4 volts. or
The ECM has commanded glow plugs OFF and the glow plug signal voltage is more than 4 volts.
Action Taken When the DTC Sets
The control module stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
The driver information center, if equipped, may display a message.
Conditions for Clearing the DTC
A current DTC Last Test Failed clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
Clear the DTC with a scan tool.
Diagnostic Aids
If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs, refer to Glow Plug System Diagnosis . When glow plugs are commanded ON by the scan tool, an internal ECM timer protects the glow plugs from damage by cycling them ON for 3 seconds and then OFF for 12 seconds.

The glow plug output feed wire nut and battery feed wire nut at the relay should be checked for proper torque, 5 N·m (44 lb in) and for corrosion.

An intermittent may be caused by the following:

Poor connections
Rubbed through wire insulation
Broken wire inside the insulation

DTC P0380 (California)
Circuit Description
The glow plug system is used to assist in providing the heat required to begin combustion during cold engine temperatures. The glow plugs are heated before and during cranking, as well as initial engine operation. The Engine Control Module (ECM) controls the glow plug ON times by monitoring coolant temperature and glow plug voltage. The California Glow Plug system has eight individual glow pllug supply circuits between the controller and the glow plugs. If the feedback voltage from the controller to the ECM is not within range, DTC P0380 will set.

Conditions for Running the DTC
The ignition is ON.

Conditions for Setting the DTC
• The glow plugs are commanded OFF and the glow plug feedback is more than 2.0 volts. or

• The glow plugs are commanded on and the glow plug feedback is not between 5.0 volts and 6.2 volts.

Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
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
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Important: If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs. When the glow plugs are commanded ON by the scan tool, an internal engine control module (ECM) timer protects the glow plugs from damage by cycling them ON for 3 seconds and the OFF for 12 seconds. The glow plug relay battery feed wire nut at the relay should be tested for proper torque. The California glow plug system will send the following voltages, or signals to the ECM:

01-04 Chevrolet Silverado/GMC Sierra C/K2500HD C/K3500 6.6L LB7 Engine with a No Charge Condition with DTC P0380 P0621- kw battery diesel ECM fuse generator voltage #PIT3121 - (Aug 20, 2004)
04 Chevrolet Silverado GMC Sierra C/K2500HD C/K3500 6.6L LB7 Engine- with a No Charge Condition with DTC P0380 P0621
.

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:
Vehicles equipped with the 6.6 Duramax diesel engines RPO LB7 may have a no charge condition that may be accompanied by DTC P0380 and P0621. Following published diagnostics for DTC P0621 or a no charge condition may lead to unnecessary generator or ECM replacement.

Recommendation/Instructions:
Following published diagnostics for DTC P0380, P0621 or a no charge condition may lead to unnecessary generator or ECM replacement. You should first check the 175-amp battery fuse. If the 175-amp battery fuse OR circuit 506 is open, no voltage will be present on circuit 506 at the PCM. This will cause the P0380 to set. The ECM monitors the glow plug signal using circuit 506. The ECM expects to see battery voltage on circuit 506 when the glow plugs are commanded on. If no voltage is present on circuit 506, the ECM will stop sending the turn on voltage to the generator L terminal circuit 25, causing the no charge condition and the P0621 to set.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

Thanks Max
So I 've probably lost a injector or will the 0380 set the 0302

If your glow plugs aren't working, I could maybe see it causing the misfire code. The PCM only monitors for misfires for the first 30 seconds of continuous idle, IIRC.

Well I left it at the dealer hope they know what their doing? :confused:
It's the only dealer around that sells alot of trucks (work trucks, ect)

What exactly is a fuel system/injector cleaning for 200.00
Is it worth it?
Is it just B.S.?