DTC P1380 Misfire Detected - Rough Road Data Not Available. Chevrolet Corvette 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Corvette 🢒 DTC 🢒 DTC P1380 Misfire Detected - Rough Road Data Not Available

Circuit Description

The PCM detects engine misfire by detecting variations in crankshaft deceleration between firing strokes. For accurate detection of engine misfire the PCM must distinguish between crankshaft deceleration caused by actual misfire and deceleration caused by rough road conditions. The antilock brake system (ABS) can detect if the vehicle is on a rough road based on wheel acceleration/deceleration data supplied by the wheel speed sensors. If the ABS detects rough road above a predetermined threshold, this information is sent to the PCM via serial data. The PCM can then take the rough road into account when calculating misfire. Even if the ABS is malfunctioning and cannot detect rough roads, the misfire diagnostic will continue to run. However, if a misfire DTC sets, this additional DTC also sets indicating that rough road data was not available during the misfire calculation due to an ABS malfunction.

Conditions for Running the DTC

•	DTCs P0101, P0102, P0103, P0335, P0336, P0742, P1120, P1121, P1220, P1221 are not set.

•	The vehicle speed is above 16 km/h (10 mph).

•	The engine load is less than 60 percent.

•	Engine misfire is detected (DTC P0300 set).

•	The engine speed is less than 3200 RPM.

Conditions for Setting the DTC

An ABS system malfunction exists preventing the PCM from receiving rough road detection data.

Conditions for Clearing the MIL/DTC

•	A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.

•	A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.

•	Use a scan tool in order to clear the MIL/DTC.

Conditions for Clearing the MIL/DTC

•	The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

•	A last test failed, or current DTC, clears when the diagnostic runs and does not fail.

•	A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

•	Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids

Important:

•	Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.

•	For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616 . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

For an intermittent condition, refer to Symptoms .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Service the ABS before diagnosing for a misfire, because an actual engine misfire may or may not exist. The following two examples illustrate how this DTC can be set with or without an actual engine misfire:

•	There was an actual engine misfire during an ABS malfunction.

•	The vehicle operator drove on a rough road, the ABS may not detect this due to a malfunction, and the PCM interpreted the variations in crankshaft speed caused by the rough road as a misfire.

Step	Action	Values	Yes	No
1	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Diagnostic System Check - ABS in Antilock Brake System	Go to Powertrain On Board Diagnostic (OBD) System Check