Circuit Description
The ignition 1 relay is controlled by the body control module (BCM). The ignition 1 relay contacts are supplied a hot at all times from the fuse block underhood. The relay supplies power to several components when the vehicle is in the RUN or CRANK power mode. When the ignition switch is placed in the RUN or CRANK position, the BCM will receive an ignition 1 signal from the ignition switch and turn ON the ignition 1 relay. When the ignition switch is in the OFF position, the BCM will turn OFF the ignition 1 relay. The powertrain control module (PCM) compares the ignition 1 relay output signal with the BCM class 2 serial data power mode message. If the ignition 1 voltage signal and the power mode message do not match for an allotted time, the PCM will disable the fuel injectors and DTC P2535 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2535 Ignition One Voltage High
Conditions for Running the DTC
| • | The vehicle is in PARK or NEUTRAL. |
| • | The ignition switch is OFF. |
Conditions for Setting the DTC
The ignition 1 voltage signal is higher than normal for more than 7 seconds.
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. |
Test Description
-
This relay may be a permanently integrated in the BEC on some vehicles, in this case you must replace the BEC in order to complete the repair. Refer to Engine Controls Schematics .
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views and Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 3 |
3 | Connect a test lamp between the ignition 1 voltage circuit on the body control module (BCM) side of the relay and a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 8 |
4 | Test the ignition 1 voltage circuit between the PCM and the ignition 1 relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 6 |
5 | Test the ignition 1 voltage circuit between the BCM and the ignition 1 relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 7 |
6 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 9 |
7 | Test for an intermittent and for a poor connection at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
Replace the ignition 1 relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 11 | -- | |
9 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- |
10 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC fail this ignition? | Go to Step 2 | Go to Step 12 |
12 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
