Diagnostic Instructions
DTC Descriptor
DTC P2534: Ignition 1 Switch Circuit Low Voltage
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Ignition 1 voltage
| P2534 open fuse
| P2534
| --
| P0562, P0563
|
Typical Scan Tool Data
Ignition 1 Voltage
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
|
Operating Conditions:
Ignition ON
Parameter Normal Range:
0-19 volts
|
Ignition 1 voltage
| 0 Volts
| 0 Volts
| --
|
Circuit/System Description
The transmission control module (TCM) continuously monitors the system voltage on the Ignition 1 voltage circuit every 0.025 seconds. Lower than normal voltage may be inadequate to operate the transmission control solenoids properly.
Improper solenoid operation may cause erratic transmission operation, which may result in internal damage.
Conditions for Running the DTC
| • | The engine speed is greater than 500 RPM for 5 seconds. |
| • | Ignition voltage is between 9.0 volts and 19.0 volts. |
Conditions for Setting the DTC
The TCM detects 2 volts or less on the ignition 1 voltage circuit at the TCM for 6 seconds or more.
Action Taken When the DTC Sets
| • | DTC P2534 is a Type A DTC. |
| • | The TCM turns OFF all high side drivers. |
| • | The TCM turns OFF all solenoids. |
| • | The TCM commands maximum line pressure. |
| • | the TCM freezes transmission adaptive functions. |
| • | The TCM commands the TCC OFF. |
| • | The TCM allows the vehicle to operate in transmission protection mode. |
| • | The TCM inhibits TU TD/MUMD operation. |
Conditions for Clearing the DTC
DTC P2534 is a Type A DTC.
Diagnostic Aids
| • | DTC P2534 detects a continuous open in the TCM ignition 1 switch circuit. |
| • | Observe the driver information center (DIC) messaging that would indicate the electrical system requires service. |
| • | Inspect for the following conditions: |
| - | Loose or damaged terminals at the generator |
| - | Loose or worn generator drive belt |
| • | Use the scan tool in order to inspect all other modules for voltage related DTCs. |
| • | Inspect the charging circuit for high resistance. |
| • | Inspect the vehicle battery for open or sulfated cells. |
| • | If all circuit tests are OK, ensure the transmission pass through connector and harness terminals are clean and not damaged. |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine ON, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.0 and 15.0 volts.
- Increase the engine speed to 1,500 RPM. The Ignition Voltage parameter should remain between 12.0-14.5 volts.
| ⇒ | If the voltage is not within the specified range when the engine speed is increased, refer to
Charging System Test
. |
- Ignition ON, engine OFF, accessories OFF, observe the Battery Voltage parameter on the scan tool. The Battery Voltage should be between 12.0 and 14.5 volts.
- Engine ON, accessories OFF, observe the Ignition Voltage parameter on the scan tool. The Ignition Voltage should be between 12.0 and 14.5 volts.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Engine OFF, disconnect the TCM connector. Connect the negative probe of the DMM to a good ground. Turn ON the ignition, with the engine OFF, probe the battery positive voltage circuit, TCM connector terminal 1, and the ignition 1 voltage
circuit, TCM connector terminal 12, on the harness side of the TCM 14-Way connector with the positive probe of the DMM. Measure the voltage for each circuit. The voltage should be between 11.0 and 14.5 volts.
| ⇒ | If the voltage is 0 volts, inspect the TRANS fuse, and the TCM fuse for being open. If open, test the affected circuit for a short to ground. |
| ⇒ | If the fuse is not open, test the affected circuit for an open. |
- Compare the battery positive voltage value to the ignition 1 voltage value from above. The voltage drop between the circuits should be less than 0.5 volt.
| ⇒ | If the voltage drop is greater than 0.2 volt, repair the open or high resistance in the affected circuit. |
- If all circuits and connections test normal, replace the control solenoid (w/body and TCM) valve assembly.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
| • | Refer to
Control Module References
for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming. |
