Circuit Description
The charge up circuit in the engine control module (ECM) steps up the voltage for injectors and is divided into 2 banks, common 1 and common 2. The common 1 covers injectors in cylinders 1, 2 and 3, and the common 2 covers injectors 4, 5, and 6. If the common 1 or common 2 injector charge up circuit in the ECM is excessively high or low voltage condition, this DTC will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1261 Injector Positive Voltage Control Circuit Group 1
Conditions for Running the DTC
| • | The ignition switch is ON. |
| • | The engine is running. |
| • | The battery voltage is between 10-16 volts. |
| • | Crankshaft position (CKP) sensor is not failed. |
Conditions for Setting the DTC
The ECM detects that the injector charge up circuit is insufficient charge or over charge condition.
Action Taken When the DTC Sets
| • | The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | The ECM limits fuel injection quantity for fail-safe operation. |
| • | The ECM closes the exhaust gas recirculation (EGR) valve and holds to close position. |
| • | The ECM inhibits cruise control. |
| • | The ECM limits fuel rail pressure for fail-safe operation. |
| • | The engine stops if overcharge occurs. |
Condition for Clearing the DTC
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the DTC fail this ignition? | Go to Step 3 | Go to Step 5 |
3 |
Important: The replacement engine control module (ECM) must be programmed. Replace the ECM. Refer to Engine Control Module Programming and Setup , Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming . Did you complete the replacement? | Go to Step 4 | -- |
4 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 5 |
5 | Observe the stored information, Capture Info with a scan tool. Are there any DTCs that you have not diagnosed? | System OK | |
