Series 60 DDEC V Troubleshooting

Section 56.2 Troubleshooting Flash Code 54, PID 84/FMI 12

Section 56.2
Troubleshooting Flash Code 54, PID 84/FMI 12

This diagnostic condition is typically an open sensor signal circuit. In a system without VSS Anti-tampering, the code is logged when the rpm >1500 and PW >15° and vehicle speed < 3 mph. With or without VSS Anti-tampering, mph will be limited if the code is logged.‪

Note: Code will not be logged for the first five hours of ECM/ECU life (total engine hours).

The following procedure will troubleshoot Flash Code 54.‪

Section 56.2.1
Check Vehicle Speed Sensor Circuit

Begin troubleshooting by taking the vehicle for a test drive with an assistant.‪

  1. View the diagnostic tool; select Vehicle Speed.
    1. If mph reads 0 (zero), or stays steady with the vehicle in motion, go to step 2 .
    2. If speed appears correct, refer to "56.2.6 Vehicle Speed Mechanical Checks" .
  2. Identify the speed sensor type - type one or type two.
    • The type one sensor is a magnetic pickup and may be located in one of the following locations: transmission tail shaft, wheel rim, mechanical speedometer cable. If you have a type one sensor, verify with diagnostic tool signal type - magnetic. Go to step 3 .
    • The type two sensor communicates with square wave input and output signals and requires the ECM/ECU to be configured correctly. If you have a type two sensor, verify with diagnostic tool signal type - switched.Refer to "56.2.7 Check for Short to Ground" .
  3. With ignition off, disconnect the Vehicle Interface Harness (VIH) connector.
  4. Measure resistance of VSS circuit across VIH connector pins, V-17 and V-18. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is less than 50 Ω, refer to "56.2.2 Check for Short and VSS Connectors" .
    2. If the resistance measurement is greater than 3,000 Ω or open, refer to "56.2.3 Check for Open" .
    3. If the resistance measurement is between 50 and 3,000 Ω, refer to "56.2.4 Check for Short to Ground" .
    4. Click to see this graphic in a separate window

      Figure 1. VIH-to-ECM/ECU Connector

Section 56.2.2
Check for Short and VSS Connectors

Perform the following steps to check for short.‪

  1. Disconnect VSS connector.
  2. Measure resistance between VIH connector terminals V-17 and V-18. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is less than or equal to 1,000 Ω, the signal wire V-17 or return wire V-18, are shorted together. Repair the short; refer to "56.2.7.1 Verify Repairs" .
    2. If the resistance measurement is greater than 1,000 Ω or open, go to step 3 .
  3. Measure resistance of VSS across Vehicle Speed Sensor connector pins. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is less than 50 Ω, go to step 4 .
    2. If the resistance measurement is greater than 3,000 Ω or open, go to step 4 .
    3. If the resistance measurement is between 50 and 3,000 Ω, check the terminals at the ECM/ECU VIH connector for bent, corroded, and unseated pins or sockets, on both the ECM/ECU and harness sides. If there is no damage, refer to "56.2.6 Vehicle Speed Mechanical Checks" . If there is damage, repair and refer to "56.2.7.1 Verify Repairs" .
  4. Check terminals at the VSS connectors (both sensor side and harness side) for bent, corroded, and unseated pins or sockets.
    1. If the terminals and connectors are not damaged, replace the VSS. Refer to "56.2.7.1 Verify Repairs" .
    2. If the terminals and connectors are damaged, repair them. Refer to "56.2.7.1 Verify Repairs" .

Section 56.2.3
Check for Open

Perform the following steps to check for open.‪

  1. Disconnect the ECM/ECU VIH connector and VSS connector.
  2. Install a jumper wire between sockets 1 and 2 of the VSS harness connector.
  3. Measure resistance between sockets V-17 and V-18 on the ECM/ECU VIH connector. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is less than or equal to 5 Ω, go to step 4 .
    2. If the resistance measurement is greater than 5 Ω or open, the VSS signal line V-17 or return line V-18 is open. Repair open and refer to "56.2.7.1 Verify Repairs" .
  4. Measure resistance of VSS across Vehicle Speed Sensor connector pins. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is less than 50 Ω, go to step 4 .
    2. If the resistance measurement is greater than 3,000 Ω or open, go to step 5 .
    3. If the resistance measurement is between 50 and 3,000 Ω, check the terminals at the ECM/ECU VIH connector for bent, corroded, and unseated pins or sockets, on both the ECM/ECU and harness sides. If there is no damage, refer to "56.2.6 Vehicle Speed Mechanical Checks" . If there is damage, repair and refer to "56.2.7.1 Verify Repairs" .
  5. Check terminals at the VSS connectors (both sensor side and harness side) for bent, corroded, and unseated pins or sockets.
    1. If the terminals and connectors are not damaged, replace the VSS. Refer to "56.2.7.1 Verify Repairs" .
    2. If the terminals and connectors are damaged, repair them. Refer to "56.2.7.1 Verify Repairs" .

Section 56.2.4
Check for Short to Ground

Perform the following steps to check for short to ground.‪

  1. Turn ignition OFF.
  2. Remove jumper wire.
  3. Measure resistance between sockets V-17 and V-18 and a good ground. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is greater than 1,000 Ω or open, refer to "56.2.5 Check for Short to Power" .
    2. If the resistance measurement is less than or equal to 1,000 Ω, the signal wire V-17 or return wire V-18, is shorted to ground, or wired to an unauthorized device. Repair the short; refer to "56.2.7.1 Verify Repairs" .

Section 56.2.5
Check for Short to Power

Perform the following steps to check for short to power.‪

  1. Turn ignition ON.
  2. Measure voltage at the ECM/ECU VIH connector between socket V-17 and a good ground. Also measure voltage between socket V-18 and a good ground. See Figure "VIH-to-ECM/ECU Connector" .
    Click to see this graphic in a separate window

    Figure 2. VIH-to-ECM/ECU Connector

    1. If both voltage measurements are less than 0.2 volts, go to step 3 .
    2. If either voltage measurement is greater than or equal to 0.2 volts, the VSS signal V-17 or VSS return line V-18 is shorted to the battery or some other source of voltage. Repair the short; refer to "56.2.7.1 Verify Repairs" .
  3. Check the terminals at the ECM/ECU VIH connector for bent, corroded, and unseated pins or sockets, on both the ECM/ECU and harness sides. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the terminals and connectors are not damaged, refer to "56.2.6 Vehicle Speed Mechanical Checks" .
    2. If the terminals and connectors are damaged, repair them. Refer to "56.2.7.1 Verify Repairs" .

Section 56.2.6
Vehicle Speed Mechanical Checks

Perform the following vehicle speed mechanical checks.‪

  1. Check for plugged fuel filters.
  2. Check if any metal or debris is lodged between the VSS and the pulse wheel.
  3. Check if the sensor is loose.
  4. Ensure the VSS pulse wheel is in fixed position relative to magnetic pickup.
  5. Check for proper air gap between magnetic pickup and pulse wheel.
    1. If all mechanical checks are okay, contact the Detroit Diesel Customer Support Center (313–592–58900) for review if anti-tamper = yes.
    2. If all mechanical checks are not okay, repair the mechanical failure. Refer to "56.2.7.1 Verify Repairs" .

Section 56.2.7
Check for Short to Ground

Perform the following steps to check for short to ground.‪

  1. Turn ignition OFF and disconnect the ECM/ECU VIH connector.
  2. Measure resistance between sockets V-17 and a good ground. See Figure "VIH-to-ECM/ECU Connector" .
    1. If the resistance measurement is greater than 10,000 Ω or open, contact the component supplier for instructions. The wiring is okay, but the device may be defective. Refer to "56.2.7.1 Verify Repairs" .
    2. If the resistance measurement is less than or equal to 100 Ω, the VSS signal lineV-17 is shorted to ground, Repair the short; refer to "56.2.7.1 Verify Repairs" .
Section 56.2.7.1
Verify Repairs

Perform the following steps to verify repairs.‪

  1. Turn the ignition OFF.
  2. Reconnect all the connectors.
  3. Turn the ignition ON.
  4. Clear diagnostic tool codes.
  5. Perform a road test with an assistant. Ensure the vehicle is loaded.
  6. Stop the engine.
  7. Check diagnostic tool for codes.
    1. If no codes are logged, no further troubleshooting is required.
    2. If code 84/12 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 84/12 is logged, and any other codes are logged, troubleshoot the error (refer to "56.2.1 Check Vehicle Speed Sensor Circuit" and go to step 2 ) and perform tasks.


Series 60 DDEC V Troubleshooting Guide - 6SE570
Generated on 10-13-2008

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