CM850 Electronic Control System – FAULT CODE 386

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Overview

Sensor Supply Voltage Number 1 Circuit SMALL | MEDIUM | LARGE

Circuit Description

The sensor supply voltage number 1 of the electronic control module (ECM) provides (+) 5 VDC supply for the barometric pressure sensor on the engine harness. This +5 VDC supply also powers three optional OEM devices. The three devices are digital vehicle speed sensor, remote accelerator position sensor, and OEM pressure sensor.

Component Location

The sensor supply number 1 is located in the ECM. The supply voltage is spliced off in the engine and OEM harness to each sensor it supports.

Shop Talk

High voltage on the sensor supply line can be caused by an individual sensor supply wire in the harness shorted to battery voltage or a failed ECM power supply.

On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines):

• The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The MIL lamp and fault code can also be cleared using the INSITE™ service tool.
• The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

On-Board Diagnostics (OBD) Information (Euro 4 Stage 1+ Certified Engines):

• The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• An engine torque derate will be activated after 50 hours of engine operation with the fault code active.
• The ECM turns OFF the malfunction indicator lamp (MIL) after 1 ignition cycle that the diagnostic runs and does not fail. The MIL lamp cannot be cleared using the INSITE™ service tool.
• The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Refer to Troubleshooting Fault Code t05-386