BASE AS 7W7990 - Caterpillar

Illustration 4 g03177636
Connector for the exhaust back pressure regulator
(1) 5 VDC supply
(2) Position sensor ground
(3) Position sensor signal
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors for the valve position sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 45 N (10 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM.
D. Check the screw for the J2 ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the ground connection on the ECM for abrasions and pinch points.
F. Check the harness for abrasion and pinch points from the suspect sensor to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all of the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points.
Proceed to Test Step 2.
2. Check For Active Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.
D. Use the electronic service tool in order to monitor active diagnostic codes or recently logged diagnostic codes.
E. Turn the keyswitch to the OFF position.
Diagnostic codes
Result: One or more of the diagnostic codes listed in Table 1 are active or recently logged.
Proceed to Test Step 3.
Result: None of the preceding diagnostic codes are active or recently logged.
Repair: The fault may be intermittent. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a "Wiggle Test" by using the electronic service tool in order to identify intermittent connections.
3. Measure the Supply Voltage at the Valve Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the suspect valve from the harness.
C. Turn the keyswitch to the ON position.
D. Measure the voltage between terminals 1 and 2 at the connector for the valve.
E. Reconnect the valve to the harness.
4.84 to 5.16 VDC
Result: The sensor supply voltage is out of the nominal range. The fault is in the engine harness between the valve connector and the ECM.
Repair: Repair the faulty valve connector or replace the faulty harness.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: The sensor supply voltage is correct.
Proceed to Test Step 4.
4. Verify that the Diagnostic Code is Still Active
A. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.
B. Use the electronic service tool to check for active diagnostic codes. Record all active diagnostic codes.
Diagnostic codes
Result: A -4 diagnostic