Series 60 DDEC V Troubleshooting – Section 22.2 Troubleshooting Flash Code 12, PID 187/FMI 3

Section 22.2
Troubleshooting Flash Code 12, PID 187/FMI 3

This diagnostic condition is typically:‪

• Open sensor return circuit
• Sensor signal circuit is shorted to the sensor +5 volt supply
• Throttle sensor not adjusted properly at full throttle

The following procedure will troubleshoot Flash Code 12.‪

Section 22.2.1
Multiple Code Check

Perform the following steps to check for multiple codes:‪

1. Turn ignition ON.
2. Plug in your diagnostic tool.
   1. If active code p 187/3 and any other codes except 91/3 or 100/3 are logged, refer to "22.2.2 Sensor Check" .
   2. If active code p 187/3 and codes p 91/3 or p 100/3 are logged, refer to "80.1 Troubleshooting the Vehicle Interface Harness +5 Volt Supply" .

Section 22.2.2
Sensor Check

Perform the following steps to check the sensor:‪

1. Turn ignition OFF.
2. Unplug the VSG throttle connector. (For VSG circuit, see Figure .)
3. Turn ignition ON.
4. Read active codes.
   1. If active code p 187/4 is logged, and code p 187/3 only occurs when the throttle is moved at or near full throttle (when connected), refer to "22.2.3 Check Calibration" .
   2. If active code p 187/3 is logged, and the code appears when the throttle is not at or near full throttle (when connected), refer to "22.2.4 Return Circuit Check" .
   

   Figure 1. Variable Speed Governor Circuit

Section 22.2.3
Check Calibration

Perform these additional steps to check the calibration of the sensor:‪

1. Plug in the VSG throttle connector.
2. Turn ignition ON.
3. Plug in the diagnostic tool.
4. Display VSG counts.
5. Dial throttle to Full Throttle.
   1. If the VSG counts are greater than 968, adjust the maximum throttle travel. If not adjustable, replace the throttle control.
   2. If the VSG counts are less than 968, refer to "22.2.4 Return Circuit Check" .

Section 22.2.4
Return Circuit Check

Perform these steps to check the return circuit:‪

1. Place the transmission in neutral.
2. Turn ignition OFF.
3. Install a jumper wire between pin A (V-60) and pin B (V-14) of the VSG throttle harness connector.
4. Disconnect the vehicle harness connector at the ECM/ECU.
5. Enable VSG control. (This may require the ignition be turned on.)
6. Measure resistance between sockets V-60 and V-14 on the vehicle harness connector. See Figure "ECM/ECU Vehicle Interface Harness Connector" .
   1. If the resistance is less than or equal to 5 Ω, go to step 7 .
   2. If the resistance is greater than 5 Ω , the return line V-60 is open, repair the open. Refer to "22.2.6.1 Verify Repairs" .
7. Inspect terminals at the VSG connectors (sensor side and harness side) for bent, corroded and unseated pins or sockets. See Figure "ECM/ECU Vehicle Interface Harness Connector" .
   1. If the VSG connector terminals are damaged, repair terminals and/or connectors. Refer to "22.2.6.1 Verify Repairs" .
   2. If the VSG connector terminals are in good condition with no signs of damage, refer to "22.2.5 Check for Short to Battery (+)" .
   

   Figure 2. ECM/ECU Vehicle Interface Harness Connector

Section 22.2.5
Check for Short to Battery (+)

Perform these steps to check for short to battery (+).‪

1. Turn ignition OFF. Unplug VSG connector.
2. Turn ignition ON. Measure voltage between V-14 and battery ground. See Figure "ECM/ECU Vehicle Interface Harness Connector" .
   1. If measured voltage is less than or equal to 0.2 volts, refer to "22.2.6 Check for Short" .
   2. If measured voltage is greater than 0.2 volts, signal wire is shorted to 12/24 volt source. Repair or replace V-14 circuit. Refer to "22.2.6.1 Verify Repairs" .

Section 22.2.6
Check for Short

To check for short, perform the following:‪

1. Turn ignition OFF. Unplug vehicle 68-pin connector and the VSG connector.
2. Turn ignition ON. Enable VSG. Refer to OEM guidelines.
3. Measure resistance between V-11 and V-14. See Figure "Variable Speed Governor Circuit" .
   1. If resistance is greater than 5 Ω, check ECM/ECU connector. Refer to "22.2.6.1 Verify Repairs" .
   2. If resistance is less than 5 Ω, wire V-11 (5-volt supply) is shorted to V-11 (signal). Repair short or replace wire. Refer to "22.2.6.1 Verify Repairs" to verify repairs.
   

   Figure 3. Variable Speed Governor Circuit

Section 22.2.6.1
Verify Repairs

Perform the following steps to verify repairs.‪

1. Turn ignition OFF and reconnect all connectors.
2. Set parking brake, transmission in Neutral.
3. Turn ignition ON and clear the codes.
4. Start and run the engine for one minute then stop the engine.
5. Check the diagnostic tool for codes.
   1. If no codes are displayed, no further troubleshooting is required.
   2. If code p 187/3 is not logged, and other codes are logged, refer to "18.3 First Step for Diagnosing a Fault Within the DDEC System" .
   3. If code p 187/3 is logged, and other codes are logged, review this section again.Refer to "22.2.1 Multiple Code Check" . If the code is still logged, call the DDC Customer Support Center (313–592–5800).