This condition is typically a short circuit.
91.2.1
Short Circuit Check
Check as follows:
1. Disconnect the TCO Sensor.
2. Disconnect the 120–pin MCM connector.
3. Measure the resistance
[a]If the resistance is less than 5k Ω, repair the short between the 120–pin MCM
connector wire 52 and 112. See Figure 91-2. Refer to section 91.2.1.1.
[b] If the resistance is greater than 5k Ω, go to step 4.
4. Measure the resistance between pin 2 of the TCO Sensor connector and ground.
[a] If the resistance is less than 5k Ω, repair the short circuit between pin 2 of the TCO
Sensor connector and ground. Refer to section 91.2.1.1.
[b] If the resistance is greater than 5k Ω, contact the Detroit Diesel Customer Support
Center (313–592–5800) for authorization to replace the MCM.
91.2.1.1 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.
