81.1 SPN 1071/FMI 3
This fault code indicates that there is a short to power.
81.1.1
Short to Power Check
Check as follows:
1. Turn the ignition OFF.
2. Disconnect the fan control solenoid connector.
3. Turn the ignition ON (key On, engine OFF).
4. Measure the voltage between pin 1 of the fan control solenoid connector and ground.
[a] If the voltage is greater than 11.5 volts, repair the short to power between pin 1
of the fan control solenoid connector and pin 33 of the 120–pin MCM connector.
Refer to section 81.1.1.1.
[b] If the voltage is less than 11.5 volts, replace the fan control solenoid. Refer to section
81.1.1.1.
81.2 SPN 1071/FMI 4
This fault indicates that there is a short to ground.
81.2.1
Short to Ground Check
Check as follows:
1. Turn the ignition OFF.
2. Disconnect the fan control solenoid.
3. Disconnect the 120–pin MCM connector.
4. Measure the resistance between pin 1 of the fan control solenoid and ground.
[a] If the resistance is less than 5 Ω, repair the short to ground between pin 1 of the fan
control solenoid and pin 33 of the 120–pin MCM connector. Refer to section 81.2.1.1.
[b] If the resistance is greater than 5 Ω, repair the short to ground between pin 2 of the fan
control solenoid and pin 91 of the 120–pin MCM connector. Refer to section 81.2.1.1.
81.3 SPN 1071/FMI 5
This fault code indicates that there is an open circuit.
81.3.1
Open Circuit Check
Check as follows:
1. Check for multiple codes.
[a] If SPN 647/5, SPN 1072/5 and SPN 1071/5 are active repair the open in between
the pin 91 of the 120–pin MCM connector and the fan and the Jake Brake solenoids.
Refer to section 81.3.1.1.
[b] If only SPN 1071/5 is active, go to step 2.
2. Disconnect the fan control solenoid connector.
3. Turn the ignition ON (key On, engine OFF).
4. Measure the voltage between pin 1 and 2 of the fan control solenoid connector.
[a] If the voltage is less than 11.5 volts, go to step 5.
[b] If the voltage is between 11.5 and 13.5 volts, replace the fan control solenoid.
Refer to section 81.3.1.1.
5. Measure the voltage between pin 2 of the fan control solenoid connector and ground.
[a] If the voltage is less than 11.5 volts, repair the open between pin 2 of the fan control
solenoid connector and pin 91 of the 120–pin MCM connector. Refer to section 81.3.1.1.
[b] If the voltage is greater than 11.5, repair the open between pin 1 of the fan control
solenoid connector and pin 33 of the 120–pin MCM connector. Refer to section 81.3.1.1.
