Usage:
The electronic control system provides two sinking drivers to annunciate the various conditions. The drivers are capable of sinking 300 mAmp. The J1 Customer Connector has diagnostic outputs, which can be used to drive a relay, audible or visual alarm.
- * The Check Engine Lamp alerts the operator that the presence of diagnostic conditions exist in the system (other than those that use flash codes).
- * The Warning Lamp output alerts the operator about engine and transmission conditions. The output to the lamps indicate the following conditions.
Check Engine and Warning Lamp Diagram
Lamp Driver Electrical Specifications
Electrical characteristics of the ECM low side drivers used for the Check Engine Lamp, Warning Lamp, and Multi-Function Output #1 ECM outputs are maximum current of 0.30 amperes.
These circuits are low side drivers because the ECM provides a path to ground to activate the lamp or other device connected to it. Caterpillar does not require dedicated circuit protection for these circuits. The engine control does not have diagnostic codes associated with the lamp circuits.
Check Engine Lamp Operation
An OEM installed Check Engine Lamp is required to indicate a control system malfunction (diagnostic condition) to the driver, for diagnosing control system component failures.
On power up (ignition key ON, engine OFF), the Check Engine Lamp will come on for five seconds and turn off indicating the lamp circuit is functional. Any time there is any Active diagnostic codes, the lamp will flash on five seconds, blink off, etc.
Viewing Diagnostic Flash Codes
Caterpillar's proprietary two-digit diagnostic flash codes can be prompted for the Check Engine Lamp. Active or logged codes (occurring since ECM power up) may be determined from the Check Engine Lamp as described below.
1. Ensure the Cruise On/Off Switch is in the OFF position.
2. Hold the Set/Resume Switch in either the Set or Resume position until the lamp begins to flash (release the Set/Resume Switch).
3. Count the flashes (this is the first digit), a brief pause will occur, the second digit of the flash code will follow. All Active or logged codes (occurring since ECM power up) will then follow in the same manner with a 5 second pause between codes. If you should miss a code, repeat step 2 and step 3 and the information will be repeated.
NOTE: It is suggested the Diagnostic Flash Codes only be used to indicated the nature of a diagnostic code occurrence, not to perform detailed troubleshooting. Troubleshooting should be performed using SAE J1587 PID/FMI Diagnostic Codes obtained via an electronic service tool or digital dash display.
Warning Lamp Operation
Engine Monitoring requires an additional OEM installed warning lamp in order to alert the operator of an engine problem detected by the ECM. That action may be taken by the ECM in order to protect the engine. The lamp is on continuously while the engine is in the Warning mode. The lamp flashes when in the Derate, indicating the ECM is reducing available engine speed, vehicle speed, or power.