Series 60 DDEC V Troubleshooting – Section 76.2 Troubleshooting Flash Code 86, PID 73, 108/FMI 3

Section 76.2
Troubleshooting Flash Code 86, PID 73, 108/FMI 3

The following procedure will troubleshoot Flash Code 86. ‪

Section 76.2.1
Multiple Code Check

Perform the following steps to check for multiple codes.‪

1. Turn ignition ON.
2. Plug in diagnostic tool.
3. Read active codes.
   1. If active code p 73/3 was logged, and no other codes were logged, refer to "76.2.3 Sensor Check" .
   2. If active code p 73/4 and any other codes were logged, refer to "76.2.4 Return Circuit Check" .
   3. If active code p 108/3 was logged, refer to "76.2.2 Check Barometric Pressure Sensor" .
   4. If any codes other than p 73/3 and p 108/3 were logged, refer to "80 Vehicle Interface Harness" .

Section 76.2.2
Check Barometric Pressure Sensor

Check for a faulty Barometric Pressure Sensor as follows:‪

1. Turn the ignition ON but leave the engine OFF.
2. Using Detroit Diesel Diagnostic Link (DDDL) or a Diagnostic Data Reader (DDR) compare Barometric Pressure to Air Inlet Pressure.
   1. If they are within 4.1 kPa (0.6 psi) the sensor is not faulty and has not caused the code.
   2. If the differential is greater, replace the Barometric Pressure Sensor and check for codes. If there are no codes your troubleshooting is complete. If there are still codes, refer to "76.2.3 Sensor Check" .

Section 76.2.3
Sensor Check

Perform the following steps to check the pressure sensor.‪

1. Turn ignition OFF.
2. Disconnect the Pressure Sensor.
3. Turn ignition ON.
4. Start engine and operate in the PRESSURE mode.
5. Read active codes.
   1. If active code 73/3 and any other codes were logged, refer to "76.2.5 Check for Short to +5 Volts" .
   2. If active code 73/4 and any other codes except 73/3 were logged, refer to "76.2.4 Return Circuit Check" .

Section 76.2.4
Return Circuit Check

Perform the following steps to check the return circuit.‪

1. Turn vehicle ignition OFF.
2. Disconnect the vehicle harness connector at the ECM/ECU. See Figure "ECM/ECU Vehicle Harness Connector" and see Figure "Pump Pressure Sensor" .
3. Install a jumper wire between pins A and B of the PSG sensor harness connector.
   

   Figure 1. Pump Pressure Sensor

4. Measure resistance between sockets V-29 and V-60 on the vehicle harness connectors.
   

   Figure 2. ECM/ECU Vehicle Harness Connector

   1. If the resistance measurement is less than or equal to 5 Ω, go to step 5 .
   2. If the resistance measurement is greater than 5 Ω, or open, the return line (circuit V-60) is open. Repair the open and refer to "76.2.7.1 Verify Repairs" .
5. Inspect terminals at the sensor connector (both the sensor and harness side) for damage: bent, corroded, and unseated pins or sockets.
   1. If the terminals and connectors are damaged, repair them and refer to "76.2.7.1 Verify Repairs" .
   2. If the terminals and connectors are not damaged, replace the sensor and refer to "76.2.7.1 Verify Repairs" .

Section 76.2.5
Check for Short to +5 Volts

Perform the following steps to check for a short to the +5 volts.‪

1. Turn ignition OFF.
2. Disconnect the vehicle harness connectors at the ECM/ECU.
3. Measure resistance between sockets V-11 and V-29 on the vehicle harness connector.
   1. If the resistance measurement is greater than 100 Ω or open, refer to "76.2.6 Check for Short to Battery +" .
   2. If the resistance measurement is less than or equal to 100 Ω, the signal line (#749) is shorted to the engine +5 volt line (#916). Repair the short and refer to "76.2.7.1 Verify Repairs" .

Section 76.2.6
Check for Short to Battery +

Perform the following steps to check for a short to battery.‪

1. Remove both fuses to the ECM/ECU.
2. Disconnect the vehicle harness and 5-way power connectors at the ECM/ECU.
3. Measure resistance between socket V-29 on the engine harness connector and battery (+).
4. Measure resistance between socket V-29 of the vehicle harness connector, V-61 and V-65..
   1. If the resistance measurement for all readings is greater than 100 Ω or open, .
   2. If the resistance measurement is less than or equal to 100 Ω, a short exists between the signal line (V-29) and battery (+). Repair short and reinsert fuses. Refer to "76.2.7.1 Verify Repairs" .
5. Inspect terminals at the ECM/ECU connectors (both ECM/ECU and harness side) for damage: bent, corroded, and unseated pins or sockets.
   1. If terminals and connectors are damaged, repair them. Refer to "76.2.7.1 Verify Repairs" .
   2. If terminals and connectors are not damaged, install a test ECM/ECU. Refer to "76.2.7 Final Check" .

Section 76.2.7
Final Check

Perform the following steps to do a final check.‪

1. Reconnect all connectors.
2. Turn vehicle ignition ON.
3. Clear codes.
4. Start and run the engine for one minute.
5. Stop engine.
6. Check diagnostic tool for active codes.
   1. If no codes are logged, troubleshooting is complete.
   2. If active code 73/3 is logged, install a test ECM/ECU. Refer to "76.2.7.1 Verify Repairs" .
   3. If any codes except code 73/3 are logged, refer to "18.3 First Step for Diagnosing a Fault Within the DDEC System" , to service other codes.

Section 76.2.7.1
Verify Repairs

Perform the following steps to verify repairs.‪

1. Turn ignition switch OFF.
2. Reconnect all connectors.
3. Turn ignition ON.
4. Clear codes.
5. Start and run the engine for one minute.
6. Stop engine.
7. Check diagnostic tool for inactive codes.
   1. If no codes are logged, troubleshooting is complete.
   2. If code 73/3 is not logged, and other codes are logged, refer to "18.3 First Step for Diagnosing a Fault Within the DDEC System" , to service other codes.
   3. If code 73/3 is logged, and other codes are logged, all system diagnostics are complete. Review this section from the first step to find the problem. Refer to "76.2.1 Multiple Code Check" .