Series 60 DDEC V Troubleshooting – Section 73.5 Troubleshooting Flash Code 81, PID 173/FMI 3

Section 73.5
Troubleshooting Flash Code 81, PID 173/FMI 3

Typically, the exhaust gas temperature circuit failed high is caused by an open signal or short to battery +. Perform the following procedures to troubleshoot code p 173/3.‪

Section 73.5.1
Check for Open and Short

Check for open as follows:‪

1. Disconnect the Exhaust Temperature Sensor connector.
2. Install a jumper wire between the two pins at the ET Sensor. See Figure "Exhaust Temperature Sensor" .
3. Unplug the vehicle harness connector at the ECM/ECU.
4. Measure resistance between V-60 of the VIH connector and V-23 connector; see Figure "Exhaust Temperature Sensor" .
   1. If resistance measures less than 5 Ω, go to step 5 .
   2. If resistance is greater than 5 Ω, either the circuit V-60 is opened, or V-23 is open. Repair the open or replace the wire and test. Refer to "73.5.1.1 Verify Repair" .
5. Remove the jumper and measure resistance again between V-60 and V-23; see Figure "Exhaust Temperature Sensor" .
   

   Figure 1. Exhaust Temperature Sensor

   1. If the reading is greater than 400 Ω, the resistor between circuit V-60 and V-23 has failed. Replace the resistor or replace the harness.
   2. If the reading is less than 400 Ω, replace the ETS, and refer to "73.5.1.1 Verify Repair" .

Section 73.5.1.1
Verify Repair

Perform the following steps to test the repair:‪

1. Connect all removed connectors. Start and run the engine.
2. Perform road test.
3. Plug in diagnostic tool and read active codes.
   1. If no codes display, repairs are complete.
   2. If code 81 displays, review the procedure for checking exhaust gas temperature circuit failed high; refer to "73.5.1 Check for Open and Short" . If this is the second time through the procedure, call the DDC Customer Support Center (313–592–5800) or try a test ECM/ECU.