Engine Controls - Revised DTC P0201-P0208 Diagnosis
File In Section: 06 - Engine/Propulsion SystemBulletin No.: 02-06-04-049
Date: September, 2002
SERVICE MANUAL UPDATE
Subject:
Revised DTC P0201-P0208
Models:
2001-2002 Chevrolet Silverado Pickup Models
2001-2002 GMC Sierra Pickup Models with 6.6L Duramax(TM) Diesel Engine (VIN 1 - RPO LB7)
This bulletin is being issued to revise DTC P0201 - P0208 in the Engine Controls - 6.6L sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.
The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.
The diagnostic information and procedures for DTC P0201-P0208 have been revised in the above applications to reflect the change in the tool used to diagnose the circuit faults. Using a test lamp may not find wiring insulation problems that will allow the high voltage to go to ground. Using a DMM will find any circuit insulation problems.
Circuit Description
The fuel injection control module (FICM) supplies high voltage to each fuel injector on the injector supply voltage circuits. The FICM enables each fuel injector by grounding the command circuit between the FICM and the fuel injector. The FICM monitors the status of the injector supply voltage circuits and the fuel injector command circuits. When a fuel injector circuit condition is detected by the FICM, all of the fuel injectors on the affected injector supply voltage circuit will be disabled. If a circuit condition is detected on a fuel injector circuit for cylinders 1, 4, 6, or 7, DTCs P0201, P0204, P0206, P0207 will set, along with DTC P1261. If a circuit condition is detected on a fuel injector circuit for cylinders 2, 3, 5, or 8, DTCs P0202, P0203, P0205, P0208 will set, along with DTC P1262.
Conditions for Running the DTC
^ DTCs U1800, and U2104 are not set.
^ The engine is running.
^ The charging system voltage is between 6 - 18 volts.
Conditions for Setting the DTC
^ The FICM detects an incorrect current on a fuel injector circuit.
^ The condition exists for less than 1 second.
Action Taken When the DTC Sets
^ The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
^ The control module disables the set of fuel injectors that have a concern.
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.
Test Description
The numbers below refer to the step numbers on the diagnostic table shown.
2. This step verifies that the condition is not intermittent.
4. This step determines which set of fuel injectors the circuit condition is affecting. If DTC P1261 is set, then a condition exists on cylinders 1, 4, 6, or 7. If DTC P1262 is set, then a condition exists on cylinders 2, 3, 5, or 8.
5. This step tests if a ground is constantly being applied to the fuel injectors.
6. This step isolates which circuit is causing the condition. If the test lamp turns OFF when a multi-way connector is disconnected, test the affected circuits for a short to ground.
7. This step tests for an open circuit. If the DMM displays OL on all of the fuel injector circuits, the ignition voltage circuit is open.
8. This step tests for an open circuit. If the DMM displays OL on one of the fuel injector circuits, the fuel injector command circuit is open.
9. This step tests for excessive resistance in a fuel injector circuit.
10. This step is testing for a short between the ignition feed circuit and the fuel injector command circuit. If the resistance of the circuits is less than 0.3 ohms, test for a short between the circuits. If a short cannot be found, the fuel injector may be the cause of the condition. The normal fuel injector resistance is between 0.3-0.4 ohms.
11. This step tests for a short to voltage on a fuel injector circuit. If the DMM displays battery voltage, a short to voltage is the cause of the condition.
12. This step isolates which circuit is causing the condition. If the DMM display changes to 0 volts when a multi-way connector is disconnected, test the affected circuits for a short to voltage.
13. This step tests if a ground is constantly being applied to the fuel injectors.
14. This step isolates which circuit is causing the condition. If the DMM displays OL when a multi-way connector is disconnected, test the affected circuits for a short to ground.
15. This step tests for an open circuit. If the DMM displays OL on all of the fuel injector circuits, the ignition voltage circuit is open.
16. This step tests for an open circuit. If the DMM displays OL on one of the fuel injector circuits, the fuel injector command circuit is open.
17. This step tests for excessive resistance in a fuel injector circuit.
18. This step is testing for a short between the ignition feed circuit, and the fuel injector command circuit. If the resistance of the circuits is less than 0.3 Ohms, test for a short between the circuits. If a short cannot be found, the fuel injector may be the cause of the condition. The normal fuel injector resistance is between 0.3-0.4 ohms.
19. This step tests for a short to voltage on a fuel injector circuit. If the DMM displays battery voltage, a short to voltage is the cause of the condition.
20. This step isolates which circuit is causing the condition. If the DMM display changes to 0 volts when a multi-way connector is disconnected, test the affected circuits for a short to voltage.
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