Circuit Description
The brake booster pressure sensor measures the negative air pressure or vacuum reserve in the brake booster assembly. The engine control module (ECM) supplies the following circuits to the brake booster pressure sensor:
| • | A 5-volt reference circuit |
| • | A signal circuit |
| • | A low reference circuit |
During engine running conditions, the brake booster pressure sensor signal circuit voltage varies, depending on the vacuum reserve internal to the brake booster. If the ECM detects that the brake booster pressure sensor signal circuit voltage is at a high voltage, then DTC P0558 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0558 Brake Booster Pressure Sensor Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The ignition voltage is greater than 11 volts, but less than 18 volts. |
| • | DTC P0558 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ECM detects greater than 4.89 volts on the brake booster sensor signal circuit for more than 12.5 milliseconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores the information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | 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 emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End Views: Engine 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 | Observe the brake booster pressure sensor voltage parameter with a scan tool. Is the brake booster pressure sensor voltage parameter more that the specified value? | 4.8 V | Go to Step 4 | Go to Step 3 |
3 |
Is the brake booster pressure sensor voltage parameter more than the specified value? | 4.8 V | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections |
4 | Is DTC P0641 also set? | -- | Go to Step 5 | |
5 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 6 |
6 |
Is the voltage greater than the specified value? | 5.2 V | Go to Step 9 | Go to Step 7 |
7 |
Is the brake booster pressure sensor voltage parameter more than the specified value? | 0.2 V | Go to Step 12 | Go to Step 8 |
8 |
Is the voltage more than the specified value? | 1 V | Go to Step 10 | Go to Step 14 |
9 | Test the brake booster pressure sensor 5-volt reference circuit for a short to voltage. refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
10 | Test the brake booster pressure sensor low reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 |
11 | Test the brake booster pressure sensor low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
12 | Test the brake booster pressure sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
13 | Test for shorted terminals and poor connections at the engine control module (ECM) wire harness electrical connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
14 | Replace the brake booster pressure sensor. Did you complete the replacement? | -- | Go to Step 16 | -- |
15 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 16 | -- |
16 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 17 |
17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
