Circuit Description
Rough roads cause torque on the tires that is transmitted to the powertrain.
This slows down the crankshaft giving the appearance of a misfire. The electronic
brake and traction control module (EBTCM) determines rough road surfaces
using input from the wheel speed sensors. The EBTCM then sends the rough
road data to the PCM via class 2 serial data. The PCM uses the
rough road data to enhance the misfire diagnostic. The data allows the
PCM to distinguish the crankshaft speed variations caused by rough road
surfaces from those caused by true misfires. If the EBTCM is unable
to identify rough road conditions while the PCM detects a misfire condition,
DTC P1380 will set.
Conditions for Running the DTC
| • | The engine load is less than 100 percent. |
| • | The engine speed is less than 6500 RPM. |
| • | The vehicle speed is more than 1 km/h (0.6 mph). |
| • | A misfire DTC is occurring and requesting the MIL to be illuminated. |
Conditions for Setting the DTC
The PCM detects an EBTCM rough road sensing error.
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. |
Diagnostic Aids
DTC P1380 set indicates that the ABS/TCS system has detected
a malfunction which will not allow the EBTCM to transmit the correct rough
road data to the PCM.
If the condition is intermittent, refer to
Intermittent Conditions
.
