Circuit Description
The fuel injector control module (FICM) activates the fuel injector. The engine control module (ECM) signals the FICM to turn ON the injectors through the fuel injector control circuits. The FICM self monitors the supply voltage whenever the ignition is ON. If the FICM senses a low voltage condition, DTC P1550 will set.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | DTC U1800 or U2104 are not set. |
Conditions for Setting the DTC
The FICM detects low supply voltage.
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. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 | Do any other DTCs set? | Go to Step 3 | |
3 |
Important: Use connection pin adapters from J 35616 Adapter Kit.
Does the voltage measure more than 10 volts? | Go to Step 5 | Go to Step 4 |
4 | Repair high resistance in the FICM power or ground circuits. Did you complete the repair? | Go to Step 6 | -- |
5 | Replace the FICM. Refer to Fuel Injector Control Module Replacement . Did you complete the replacement? | Go to Step 6 | -- |
6 |
Does the DTC run and pass? | Go to Step 7 | Go to Step 2 |
7 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK |
