Circuit Description
When an ignition key is inserted into the ignition lock cylinder and switch to ON, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the body control module (BCM). The BCM then compares this value to a value stored in memory, learned key code. If the value is correct the BCM sends the fuel enable password via the serial data circuit to the powertrain control module (PCM).
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3055 No Transponder Modulation/No Transponder
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The BCM is unable to measure the ignition key transponder value. This may be due to a damaged or missing transponder, a non PASS-Key III (PK3) key, or a damaged theft deterrent exciter module.
Action Taken When the DTC Sets
Important: If the BCM is unable to measure the ignition key transponder value for 30 consecutive seconds, after the vehicle has started, the BCM will enter a fail enable state. The BCM sends a message via the serial data circuit to the driver information center (DIC) to display the Service Theft - VTD Fail Enable message. The vehicle will not stall or stop running. If the BCM is in a fail enable state when the ignition is turned to OFF, it will remain fail enabled until the next time the vehicle is started. If the BCM is fail enabled, the vehicle theft deterrent (VTD) system is NOT active and the vehicle will start. The BCM WILL send its enable password even if a transponder value is not received. The BCM will remain fail enabled until the module measures a valid key transponder value for 5 consecutive ignition cycles then the BCM will exit the fail enable state.
| • | The vehicle will not start. |
| • | The BCM sends the fuel disable password via the serial data circuit to the PCM. |
| • | The DIC displays Starting Disabled Due To Theft message. |
Conditions for Clearing the MIL/DTC
| • | The BCM clears the current status of the DTC when it senses a valid key transponder value for 5 consecutive ignition cycles. |
| The BCM clears the history status of the DTC after 100 fault-free ignition cycles. |
| • | The DTC can be cleared by using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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This step verifies the condition for setting DTC B3055 is current.
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The key must be a PASS-Key III key with an operating transponder for the VTD system to work.
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The only method to confirm whether the transponder in the key or the BCM is malfunctioning is to try an alternative PASS-Key III key in the system. The vehicle was delivered with 2 keys.
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The possibility is unlikely that more than one key will be defective. If all keys do not work, the BCM or the theft deterrent exciter module is malfunctioning.
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If the vehicle has a malfunctioning BCM that malfunctioned during an ignition cycle, the system will be in fail enabled and the vehicle will start for all keys.
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If a new key must be tried, the key must have the proper mechanical cut and the theft deterrent control module must "learn" the transponder value.
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If only one key was available for the vehicle and the replacement key does not work, the BCM or the theft deterrent exciter module is malfunctioning.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Immobilizer Schematics Connector End View Reference: Immobilizer Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | Turn ON the ignition, with the engine OFF. Is DTC B2945 set as history code? | Go to DTC B2945 | Go to Step 3 |
Is DTC B3055 set as a current code? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | |
Inspect the vehicle key for damage to the molded head and for PK3 embossed on the shank. Is the head of the key damaged or missing the PK3 embossing? | Go to Step 9 | Go to Step 5 | |
Are more than one of the vehicles keys available? | Go to Step 6 | Go to Step 8 | |
Do any of the available keys start the vehicle? | Go to Step 7 | Go to Step 8 | |
Do all of the available keys cause DTC B3055 to set? | Go to Step 8 | Go to Step 9 | |
8 | Test the security system sensor low reference, security system sensor supply voltage and ground circuits of the theft deterrent exciter module for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 9 |
Did you complete the replacement? | Go to Step 10 | -- | |
Does the replacement key cause DTC B3055 to set? | Go to Step 11 | Go to Step 16 | |
11 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections . Did find and correct the condition? | Go to Step 16 | Go to Step 12 |
12 |
Important: If a 10-Minute or 30-Minute Re-Learn Procedure is performed, all keys not learned at that time will be erased and will not be recognized. Perform the Adding Keys procedure on all keys or instruct the customer how to perform the Adding Keys procedure. Refer to Adding Keys . Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 | Does the replacement module cause DTC B3055 to set? | Go to Step 14 | Go to Step 16 |
14 | Inspect for poor connections at the harness connector of the theft deterrent exciter module. Refer to Testing for Intermittent Conditions and Poor Connections . Did find and correct the condition? | Go to Step 16 | Go to Step 15 |
15 | Replace the theft deterrent exciter module. Did you complete the replacement? | Go to Step 16 | -- |
16 |
Does the DTC reset? | Go to Step 2 | System OK |
