88341 Mercury GROMMET

Table 1
Example
Reading °C °F
Coolant Temperature 15 °C 59 °F
Inlet Manifold Air Temperature 10 °C 50 °F
"SUM"(1) 25 °C 109 °F
(1) The sum cannot be directly converted. The direct conversion of 25 °C is 77 °F.
Illustration 1 g01223271
Schematic for the air inlet heater
Test Step 1. Inspect Electrical Connectors And Wiring
Remove the electrical power from the ECM.
Illustration 2 g01223199
Typical left side engine view
(1) Air inlet heater relay
(2) Connector for the air inlet heater relay
(3) Air inlet heater
(4) J2/P2 ECM connectors
Thoroughly inspect all connections for components (1) and (3). Also, thoroughly inspect connectors (2) and (4). Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01223205
P2 terminal locations for the air inlet heater
(P2-5) Air inlet heater +Battery
(P2-79) Air inlet heater −Battery
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the air inlet heater.
Check the allen head screw at each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasion and for pinch points from the air inlet heater back to the ECM and from the air inlet heater back to the battery. Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - A problem has been found with a connector and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Use the "Air Inlet Heater Overide" to Check the Circuit
Restore the electrical power to the ECM.
Remove the electrical power from the ECM. The lamp for the air inlet heater should illuminate for two seconds. The lamp for the air inlet heater should shut off.
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Go to the "Air Inlet Heater Override" in the "Override Parameters" in the "Diagnostic Tests" under the "Diagnostics" menu on Cat ET.
Start the test and listen for a click from the air inlet heater relay. Note: The air inlet heater relay is located on the front left side of the engine.Note: Do not leave the "Air Inlet Heater Override" ON. Avoid unnecessary cycling of the air inlet heater in order to prevent the battery from discharging. The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires.Expected Result:Result 1 The relay is active.Result 2 The relay is active but the air inlet heater is suspected of having a problem.Result 3 The relay does not activate.Results:
RESULT 1 - The lamp and the relay are functioning normally.STOP
RESULT 2 - There may be a problem with the air inlet heater. Proceed to Test Step 3.
RESULT 3 - There is a problem with the relay circuit. Proceed to Test Step 4.Test Step 3. Check the Voltage at the Relay Contacts for the Air Inlet Heater
Illustration 4 g01223211
Connections for the test lamp
Remove the electrical power from the ECM.
Disconnect the wire from the relay terminal of the air inlet heater to the air inlet heater.
Fabricate two jumper wires with Deutsch sockets on one end and Deutsch pins on the other end. Strip a small amount of insulation from the middle of one jumper wire.
Disconnect J501/P501 and insert the jumper wires in the electrical connectors.
Connect a voltage test lamp from the disconnected relay terminal to the jumper wire that is connected to J501 and P501 terminals.
Restore the electrical power to the ECM.
Go to the "Air Inlet Heater Override" on Cat ET.
Start the test and watch the voltage test lamp. Note: Do not leave the "Air Inlet Heater Override" On. Avoid unnecessary cycling of the air inlet heater in order to prevent the battery from discharging. The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires.Expected Result:The test lamp turned ON and the test lamp turned OFF with the "Air Inlet Heater Override".Resul