0323582 JOHNSON SEAL, Thermostat

Illustration 1 g01064548
The ECM does not read the OEM installed auxiliary brake relay switches in order to determine operation. Only the conditions that are listed below are used to determine operation. The OEM installed auxiliary brake relay switches determine the path of the signal.In order to ensure the proper operation of the auxiliary brake, the following conditions must be met:
Engine speed is above 800 rpm.
The percent of accelerator pedal position is equal to seven percent or the percent of accelerator pedal position is less than seven percent.
The clutch pedal is released.These conditions must be met regardless of the following parameters:
Customer specified settings for the engine retarder
Auto retarder in cruise
Engine retarder minimum vehicle speedAdditional operating requirements must be met if the "Cruise/Idle On/Off Switch" is in the ON position.Cruise Control Switch in the ON positionWhen the cruise control switch is in the ON position, two special options allow the engine retarder to operate only after the driver depresses the service brake pedal. The customer programmable modes of operation are listed below:
Coast mode
Latch mode
Manual modeThe coast mode engages the engine retarder when the driver depresses the service brake pedal. The retarder disengages when the driver releases the service brake pedal.The latch mode engages the retarder when the driver depresses the service brake pedal. The retarder remains engaged until the control detects a change in a control input. Examples of a change in a control input are illustrated on the following list:
Depressing the accelerator pedal
Depressing the clutch pedal
The engine speed drops below 800 rpm.The third option for the "Engine Retarder Parameter" is manual mode. In the manual mode, the retarder operates in the same manner regardless of the position of the cruise control switch. Unlike the latch mode and the coast mode, depressing the service brake pedal is not required to initiate the retarder in the manual mode.Note: latch mode and coast mode determine engine retarder operation only when the cruise control switch is in the ON position. latch mode and coast mode do not determine engine retarder operation when the engine is active in cruise control. latch mode and coast mode require the initiation of the service brake before acting. The initiation of the service brake disengages cruise control.The "Auto Retarder in Cruise" parameter does not affect the operation of the auxiliary brake output circuit. The "Auto Retarder in Cruise" parameter is used only when the retarder is connected to the engine wiring harness.Note: If the "PTO Configuration" is programmed to "Cab Switches", to "Remote Switches", or to "Remote Throttle", the auxiliary brake output is disabled whenever the PTO On/Off circuit is on. If the vehicle is equipped with an anti-Lock brake system (ABS), the vehicle may have an additional relay in the switch circuit for the auxiliary brake solenoids. This is installed so the ABS can turn off the auxiliary brake solenoids, if necessary. The relay should have normally closed contacts.The "Engine Retarder Minimum Vehicle Speed" parameter will prevent the operation of the auxiliary brake output below the programmed vehicle speed when vehicle speed is present.The "Engine Retarder Minimum VSL Type" parameter provides the following two options:
Hard limit (default)
Soft limitWhen the parameter is programmed to the hard limit, the "Engine Retarder Minimum VSL Type" does not allow the auxiliary brake to operate under the following condition:
The vehicle speed is below the "Engine Retarder Minimum Vehicle Speed". The "Engine Retarder Minimum Vehicle Speed" is customer programmed.The soft limit also requires the vehicle speed to be equal to or greater than the programmed "Engine Retarder Minimum Vehicle Speed" in order to initiate the activation of the auxiliary brake, but the soft limit allows the operation of the auxiliary brake to continue below the programmed "Engine Retarder Minimum Vehicle Speed".The "Engine Retarder Delay" parameter provides a programmable delay after all of the basic conditions that are required to turn on the auxiliary brake are met. Once the conditions are met the ECM will delay the activation of the auxiliary brake by the programmed additional time. The programmable range is 0 to 3.0 seconds in 0.1 second increments.
Illustration 2 g01064549
Auxiliary retarder relay circuit
Illustration 3 g01064550
ECM pin locationsTest Step 1. Inspect the Electrical Connectors and the Wiring
Thoroughly inspect ECM vehicle harness connector J1/P1, and the firewall bulkhead connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on P1-28, P1-34, or P1-40:Refer to Illustration 3.
Check the allen head screws at each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and pinch points from the sensor to the ECM.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair the wiring or replace the wiring, if necessary. Repair the connectors or replace the connectors, if necessary. Ensure that all of the seals are in the proper place. Ensure that all of the connectors are connected properly. Verify that the repair eliminates the problem.STOPTest Step 2. Ensure that the Configuration Parameters are Correct
Connect Caterpillar Electronic Technician (ET) to the cab data link connector.
Turn the keyswitch to the ON position.
Access the customer specified parameter screen in order to make sure that the ECM is programmed to use the auxiliary brake output.
Ensure that the auxiliary brake output is connected to the programmed output.Expected Result:The circuit is connected to the correct ECM terminal that is selected for the auxiliary brake output.Results:
OK - Proceed to Test Step 3.
Not OK - Program the customer parameter to the correct terminal.STOPTest Step 3. Check the Parameter for "Engine Retarder Minimum Vehicle Speed"
Connect Cat ET to the cab data link connector.
Turn the keyswitch to the ON position.
Access the customer parameters screen in order to view the parameter for "Engine Retarder Minimum Vehicle Speed". Refer to Troubleshooting, "Customer Specified Parameters"for additional information regarding "Engine Retarder Minimum Vehicle Speed".
Ensure that the vehicle is not experiencing a problem due to this