DDEC III/IV Single ECM Troubleshooting – Section 15.3 Troubleshooting Flash Code 15

Section 15.3
Troubleshooting Flash Code 15

The following procedure will troubleshoot Flash Code 15.‪

Section 15.3.1
Code Check

Perform the following steps to check for codes.‪

1. Turn vehicle ignition ON.
2. Plug in diagnostic data reader (DDR) and determine which code is logged.
   1. If codes PID 110-FMI 4 are logged, refer to "15.3.2 Coolant Temperature Sensor Check" .
   2. If codes PID 175-FMI 4 are logged, refer to "15.3.3 Oil Temperature Sensor Check" .

Section 15.3.2
Coolant Temperature Sensor Check

Perform the following steps to check the coolant temperature sensor (CTS).‪

1. Turn vehicle ignition OFF.
2. Disconnect (unplug) CTS connector.
3. Start and run the engine for eight minutes.
4. Read active codes with engine still running.
   1. If code 110/4 or any other codes are logged, refer to "15.3.4 Check Coolant Temperature Sensor Connectors" .
   2. If any codes except code 110/4 are logged, refer to "15.3.6 Check for Short " .

Section 15.3.3
Oil Temperature Sensor Check

Perform the following steps to check the oil temperature sensor (OTS).‪

1. Turn vehicle ignition OFF.
2. Disconnect OTS connector. See Figure "Temperature Sensor Circuits" .
3. Start and run the engine for eight minutes.
4. Read active codes with engine running.
   1. If code 175/4 is logged, refer to "15.3.7 Check for Short " .
   2. If any codes except code 175/4 are logged, refer to "15.3.5 Check Oil Temperature Sensor Connectors" .
   

   Figure 1. Temperature Sensor Circuits

Section 15.3.4
Check Coolant Temperature Sensor Connectors

Perform the following steps to check the CTS connectors.‪

1. Check terminals at the CTS connector (both sensor and harness side) for damage; bent, corroded and unseated pins or sockets. See Figure "Temperature Sensor Circuits" .
   1. If terminals and connectors are in good condition, replace the CTS. Refer to "15.3.10 Verify Repairs" .
   2. If the terminals and connectors are damaged, repair them. Refer to "15.3.10 Verify Repairs" .
   

   Figure 2. Temperature Sensor Circuits

Section 15.3.5
Check Oil Temperature Sensor Connectors

Perform the following steps to check the OTS connectors.‪

1. Check terminals at the OTS connector (both sensor and harness side) for damage: bent, corroded and unseated pins or sockets. See Figure "Temperature Sensor Circuits" .
   1. If terminals or connectors are damaged, repair them. Refer to "15.3.10 Verify Repairs" .
   2. If terminals and connectors are not damaged, replace the OTS. Refer to "15.3.10 Verify Repairs" .
   

   Figure 3. Temperature Sensor Circuits

Section 15.3.6
Check for Short

Perform the following steps to check for a short.‪

1. Turn ignition OFF.
2. Disconnect the engine harness connector at the ECM.
3. Measure resistance between sockets P3 (#133) and Y2 (#452) on the engine harness connector. See Figure "ECM Engine Harness Connector" .
4. Measure resistance between socket P3 and a good ground.
   1. If the resistance measurement between sockets P3 and Y2, or P3 and battery ground, is less than or equal to 5 Ω, the signal line (#133) is shorted to the return line (#452) or battery ground. Repair the short. Refer to "15.3.10 Verify Repairs" .
   2. If the resistance measurement between sockets P3 and Y2 is greater than 5 Ω or open, and the resistance measurement between sockets P3 and a good ground is greater than or equal to 5 Ω or open, refer to "15.3.8 Check ECM Connectors" .
   

   Figure 4. ECM Engine Harness Connector

Section 15.3.7
Check for Short

Perform the following steps to check for a short.‪

1. Turn ignition OFF.
2. Disconnect the engine harness connector at the ECM.
3. Measure resistance between sockets R2, (#120) and Y2 (#452) on the engine harness connector. See Figure "ECM Engine Harness Connector" .
4. Measure resistance between socket R2 and a good ground.
   1. If the resistance measurement between sockets R2 and Y2, or R2 and battery (-) is less than or equal to 5 Ω, the signal line (#120) is shorted to the return line (#452) or battery ground. Repair the short. Refer to "15.3.10 Verify Repairs" .
   2. If the resistance measurement between socket R2 and Y2 is greater than 5 Ω or open, and the resistance measurement between socket R2 and a good ground is greater than or equal to 5 Ω or open, refer to "15.3.9 Check ECM Connectors" .
   

   Figure 5. ECM Engine Harness Connector

Section 15.3.8
Check ECM Connectors

Perform the following steps to check the ECM connectors.‪

1. Check terminals at the ECM engine harness connector (both ECM and harness side) for damage: bent, corroded and unseated pins or sockets. Check terminals P3 and Y2 of the ECM connector. See Figure "ECM Engine Harness Connector" .
   1. If terminals or connectors are damaged, repair them. Refer to "15.3.10 Verify Repairs" .
   2. If terminals and connectors are not damaged, reprogram the ECM. Refer to "15.3.10 Verify Repairs" .
   

   Figure 6. ECM Engine Harness Connector

Section 15.3.9
Check ECM Connectors

Perform the following steps to check the ECM connectors.‪

1. Check terminals at the ECM engine harness connector (both ECM and harness side) for damage: bent, corroded and unseated pins or sockets. Check terminals R2 and Y2 of the ECM connector. See Figure "ECM Engine Harness Connector" .
   1. If terminals or connectors are damaged, repair them. Refer to "15.3.10 Verify Repairs" .
   2. If terminals and connectors are not damaged, reprogram the ECM. Contact Detroit Diesel Technical Service Group. Refer to "15.3.10 Verify Repairs" .
   

   Figure 7. ECM Engine Harness Connector

Section 15.3.10
Verify Repairs

Perform the following steps to verify repairs.‪

1. Turn vehicle ignition OFF.
2. Reconnect all connectors.
3. Turn vehicle ignition ON.
4. Clear codes
5. Start and run the engine for one minute.
6. Stop engine.
7. Check DDR for codes.
   1. If no codes are logged, troubleshooting is complete.
   2. If code 110 or 175/4 and any other codes are logged, all system diagnostics are complete. Review this section to find the error. Refer to "15.3.1 Code Check" .
   3. If any codes except code 110 or 175/4 are logged, refer to "9.1 First Step for Diagnosing a Fault Within the DDEC System" .