Circuit Description
The engine control module (ECM) communicates with transponder key ECU assembly to verify that there are no faults. The ECM can detect the following:
| • | The ECM detects errors in its own communication with the transponder key ECU assembly. |
| • | The ECM detects errors in the communication lines. |
| • | The communication ID between the transponder key ECU assembly and the ECM is different and an engine start is attempted. |
If any one of the faults occurs, DTC B2799 will set.
Check to see that no other transponder key ECU assembly DTCs are present. If any DTCs for the transponder key ECU assembly is present, repair it first.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2799 Engine Immobilizer System Malfunction
Conditions for Running the DTC
This DTC shall run when key is inserted into key cylinder.
Conditions for Setting the DTC
| • | Error in communication between ECM and transponder key ECU assembly and in communication line. |
| • | Different communication ID is used for communication between transponder key ECU and ECM. |
Action Taken When the DTC Sets
The engine will not start.
Conditions for Clearing the DTC
The DTC will clear when conditions for setting the DTC have been repaired.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Immobilizer Schematics Connector End View Reference: Component Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 | Re-register the ECU communication ID between the transponder key ECU assembly and the engine control module (ECM). Refer to Immobilizer System Component Programming . Does the re-registered key start the vehicle? Does the engine start? | -- | Go to Step 8 | Go to Step 3 | ||||||||
3 |
Is the resistance measured less than or greater than the specified values? | ECU to ECM = less than 1 Ohm ECU to ground = 10 Kohms or greater | Go to Step 5 | Go to Step 4 | ||||||||
4 | Test the circuits for an open/high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 5 | ||||||||
5 | Install a known good transponder key ECU assembly amplifier and check that the engine starts. Does the engine start? | -- | Go to Step 6 | Go to Step 7 | ||||||||
6 | Replace the transponder key ECU assembly. Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||||
7 | Replace the ECM. Refer to Control Module References for ECM replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||||
8 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||||
