MBE 4000 DDEC VI Troubleshooting – Section 80.2 SPN 1072/FMI 4

Section 80.2
SPN 1072/FMI 4

This diagnosis is typically the Constant Throttle Valve circuit failed low.‪

Section 80.2.1
Short to Ground Check

Check as follows:‪

1. Turn the ignition OFF.
2. Disconnect the Constant Throttle Valve solenoid.
3. Measure the resistance between pin 1 of the Constant Throttle Valve solenoid and ground.
   1. If the resistance is greater than 3Ω, go to step 4 .
   2. If the resistance is less than 3Ω, replace the Constant Throttle Valve.See Figure "Constant Throttle Valve" . Refer to "80.2.1.1 Verify Repairs" .
      

      Figure 1. Constant Throttle Valve

4. Disconnect the EGR Valve.
5. Measure the resistance between pin 1 of the EGR Valve and ground. See Figure "EGR Valve" .
   

   Figure 2. EGR Valve

   1. If the resistance is greater than 3Ω, repair the short circuit to ground between pin 32 of the MCM 120–pin connector, the Constant Throttle Valve solenoid and the EGR Valve. Refer to "80.2.1.1 Verify Repairs" .
   2. If the resistance is less than 3Ω, replace the EGR Valve. Refer to "80.2.1.1 Verify Repairs" .

Section 80.2.1.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.