Series 60 DDEC V Troubleshooting – Section 77.2 Troubleshooting Flash Code 87, PID 73/FMI 4

Section 77.2
Troubleshooting Flash Code 87, PID 73/FMI 4

The signal volts dropped below 5% (normally = <0.25 volts) of the sensor supply. ‪

Section 77.2.1
Multiple Code and Sensor Check

Perform the following steps to check for codes.‪

1. Turn vehicle ignition ON.
2. Plug in diagnostic tool. Read the codes.
   1. If codes p 73/4, 100/3 or 4, 102/3 or 4, 110/3 or 4, 174/3 or 4 or 175/3 or 4 are logged, refer to "80 Vehicle Interface Harness" .
   2. If code p 73/4 is logged and no other codes are logged or if code p 73/4 is logged, and none of the following codes are logged: 100/3 or 4, 102/3 or 4, 110/3 or 4, 174/3 or 4 or 175/3 or 4, go to step 3 .
3. Turn ignition OFF.
4. Disconnect the pump pressure sensor connector and install a jumper between sockets B and C of the pump pressure sensor transducer connector. See Figure "Pump Pressure Sensor" .
   

   Figure 1. Pump Pressure Sensor

5. Turn ignition ON.
6. Start engine and operate in the PRESSURE mode.
7. Read active codes.
   1. If code p 73/3 and any other code except p 73/4 display, check to ensure the ECM/ECU and PSG sensor connectors are wired properly. If wired properly, refer to "77.2.2 Check Pressure Governor System Sensor Connectors" .
   2. If code p 73/4 and any other codes display, refer to "77.2.3 Check for Short to Return and Battery (-)" .

Section 77.2.2
Check Pressure Governor System Sensor Connectors

Perform the following steps to check the sensor connectors.‪

1. Turn ignition OFF.
2. Inspect terminals at the pump pressure sensor connectors (sensor and harness side) for damaged, bent, corroded, and unseated pins or sockets.
   1. If the terminals and connectors are not damaged, replace the sensor. Refer to "77.2.4.1 Verify Repairs" .
   2. If the terminals and connectors are damaged, repair them. Refer to "77.2.4.1 Verify Repairs" .

Section 77.2.3
Check for Short to Return and Battery (-)

Perform the following steps to check for a short.‪

1. Turn ignition OFF.
2. Remove jumper wire.
3. Remove vehicle interface harness connector (30-pin).
4. Turn ignition ON.
5. Measure resistance between V-60 and V-29.
   1. If the measured resistance is less than 1,000 Ω, the wires are shorted to each other. Replace the harness.
   2. If the measured resistance is greater than 1,000 Ω, go to step 6 .
6. Measure resistance between V-29 and battery ground.
   1. If the measured resistance is less than 1,000 Ω, the V-29 wire is shorted to the battery. Replace the harness and refer to "77.2.4.1 Verify Repairs" .
   2. If the measured resistance is greater than 1,000 Ω, refer to "77.2.4 Check for 5 Volt Open" .

Section 77.2.4
Check for 5 Volt Open

Perform the following steps to check for a 5 volt open.‪

1. Plug in the 30-pin connector for the vehicle sensor harness.
2. Turn ignition ON.
3. Measure voltage between cavity V-11 and V-60 of the transducer connector.
   1. If the measurement is less than 4.5 volts, wire V-11 is open. Repair the open or replace the harness. Refer to "77.2.4.1 Verify Repairs" .
   2. If the measurement is between 4.5 and 5.5 volts, the signal wire V-29 is open. Repair the wire and refer to "77.2.4.1 Verify Repairs" .

Section 77.2.4.1
Verify Repairs

Perform the following steps to verify repairs.‪

1. Plug in all connectors.
2. Start and run the engine.
3. Plug in your diagnostic tool and read the codes.
   1. If no codes are logged, troubleshooting is complete.
   2. If code p 73/4 is logged, review this section to find the error. Then, contact the Detroit Diesel Customer Support Center (313–592–5800).