CONTROL & MTG GP-ENGINE ELEK 4P9538 - Caterpillar

Illustration 1 g01303497
There are two types of outputs. There are driver outputs and sinking outputs. The driver outputs include the PTO Latching Output, Starter Interlock Output, and the Backup Alarm. These outputs are capable of driving 2 Amps of current at battery voltage.The sinking outputs include the Gear Indicator output. This driver is capable of 0.3 Amps.If the replacement of a relay or a solenoid is larger than the original, meaning that the replacement has a higher amperage capability, then the ECU output may disable in order to keep from destroying the internal parts of the ECU components. A diagnostic trouble code will not be generated in this type of situation. The output will appear not to function.Perform the following check:
Turn the ignition switch OFF. Disconnect the replacement relay or solenoid. Install a test lamp. Turn the ignition switch ON and activate the output. If the test lamp indicates that the output is functional, the replacement relay or solenoid must be replaced with a relay or solenoid that meets the original specifications. If replacing is necessary, a smaller relay or solenoid can be used in order to operate the larger relay or solenoid.There are three outputs that are rated for driving relays or solenoids. These outputs are rated at two amps at the chassis battery voltage.
Table 1
2 Amp Output Drivers    
Name    Pin Location    
Front Axle Differential Lock Enable Output     Chassis Connector pin 9    
PTO Enable Output     Chassis Connector pin 22    
Starter Interlock Output     Chassis Connector pin 23    
Rear Axle Differential Lock Enable Output     Chassis Connector pin 21    There are three additional low-power drivers that are capable of 300 milliamps.
Table 2
.3AMP Output Drivers    
Name    Pin Location    
Gear Driver Output     Chassis Connector pin 2    
Speed Enable Output     Chassis Connector pin 4    
Secondary Axle Differential Lock Signal     Chassis Connector pin 5    
Low Range indicator     Chassis Connector pin 10    
Check Transmission Lamp     Chassis Connector pin 25    
Output Speed Driver     Chassis Connector pin 28    
Warning Lamp     Chassis Connector pin 27    Note: Replacing a component (solenoid or relay) with one that is rated for a higher amperage may result in loss of functions. If a loss of function results after replacing a driver or relay, ensure that the replaced component is properly rated.