DTC Advanced Diagnostics: P15C5
DTC P15C5: Brake Booster Pressure Sensor A Characteristic Low Voltage
General Description
The powertrain control module (PCM) calculates a vacuum pressure (differential pressure between barometric pressure) in the brake booster based on the brake booster pressure sensor output voltage, and it is used to judge auto idle stop permission. The brake booster vacuum pressure is vacuumed by the vacuum pump which is driven by the engine, it saturates if the brake booster is vacuumed to a certain pressure. If the brake booster pressure sensor output is lower than a specified value, the malfunction is counted. If the malfunction is counted continuously for a specified time, the PCM detects a brake booster pressure sensor characteristic low voltage, and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
| Execution | Continuous |
| Sequence | None |
| Duration | 10.5 seconds or more |
| DTC Type | One drive cycle, MIL off* |
*: Auto idle stop indicator (amber) blinks.
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Vehicle speed [VEHICLE SPEED] | 19 mph (30 km/h) | - |
| No active DTCs set (prevents monitor from running) | P0555, P0557, P15C7, P15C9 | |
| Other | There is a history of vehicle stop after engine warm-up | |
| Dual speed sensor, barometric pressure (BARO) sensor, and engine coolant temperature (ECT) sensor must not be malfunctioned | ||
[ ]: HDS Parameter
Malfunction Threshold
The PCM counts up if the brake booster pressure sensor output is lower than -5 kPa (-4.6 inHg, -35 mmHg) for at least 2.1 seconds, and it counts up five times in a row.
Possible Cause
- Brake booster pressure sensor failure
- PCM internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the auto idle stop system indicator (amber) comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.
Conditions for clearing the DTC
The auto idle stop system indicator (amber) is cleared if the malfunction does not return in next trip in which the diagnostic runs. The auto idle stop system indicator (amber), the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.