821874A 1 Mercury PORT BOTTOM COWL

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 g01094719
Schematic of the circuit for the air inlet heaterTest Step 1. Inspect Electrical Connectors and Wiring
Remove power from the ECM.
Illustration 2 g01192792
Typical component locations (1) Air inlet heater relay (2) Air inlet heater (3) J2/P2 ECM connectors (4) Circuit breaker for the air inlet heater (135A)
Thoroughly inspect all connections for components (1) and (3). Also, thoroughly inspect connectors (2) and (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01093277
P2 terminal locations for the air inlet heater (P2-9) Air inlet heater − (P2-12) Air inlet heater +
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 Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
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.
Check the circuit breaker for an open condition.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. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore power to the ECM.Note: Ensure that the parameter for the "Air Inlet Heater Installation Status" is configured to Installed.
Start the "Air Inlet Heater Override" on Cat ET and observe the 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 that disables the test when the time expires.
Stop the "Air Inlet Heater Override".
Remove power from the ECM.Expected Result:One of the following diagnostic codes is active:
617-05
617-06 Results:
617-05 is Active - The ECM detects an open circuit between the air inlet heater relay and the ECM. Proceed to Test Step 3.
617-06 is Active - The ECM detects a short circuit between the air inlet heater relay and the ECM. Proceed to Test Step 4.
No Codes are Active - There are no active diagnostic codes for the air inlet heater relay. Proceed to Test Step 6.Test Step 3. Check for an Open Circuit in the Air Inlet Heater Relay's Control Circuit
Illustration 4 g01118589
Small terminals for the air inlet heater relay's control circuit (typical example)
Disconnect the wires from the small terminals for the air inlet heater relay's control circuit.
Install a test lamp across the wires.
Restore power to the ECM.
Start the "Air Inlet Heater Override" on Cat ET and observe the test lamp.Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires.
Stop the "Air Inlet Heater Override".
Remove power from the ECM.Expected Result:The test lamp illuminated while the override was active.Results:
OK - The test lamp illuminated while the override was active. The open circuit is in the relay.Repair: Replace the air inlet heater relay. Clear any diagnostic codes. Verify that the problem is resolved.STOP
Not OK - The test lamp did