2010 Cadillac CTS Sedan AWD V6-3.6L Page 1598
Circuit/System Description
The engine cooling fan system consists of a cooling fan assembly containing two electric cooling fans. The engine control module (ECM) uses two
fan control circuits and a series of three relays to command the fans ON in either high speed or low speed, depending on cooling requirements. To
operate the fan, the ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. The driver is
equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted
to a voltage by monitoring the feedback voltage. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at
full speed.
Conditions for Running the DTC
* The ignition voltage is between 10-18 volts.
* The engine speed is greater than 80 RPM.
* The ECM driver transitions from ON to OFF or from OFF to ON.
* DTC P0480, P0481, P0691, P0692, P0693, and P0694 run continuously when the conditions above are met for greater 5 mS.
Conditions for Setting the DTC
P0480
The ECM detects an open in the cooling fan relay 1 control circuit.
P0481
The ECM detects an open in the cooling fan relay 2 control circuit.
P0691
The ECM detects a short to ground in the cooling fan relay 1 control circuit.
P0692
The ECM detects a short to voltage in the cooling fan relay 1 control circuit.
P0693
The ECM detects a short to ground in the cooling fan relay 2 and 3 control circuit.
P0694
The ECM detects a short to voltage in the cooling fan relay 2 and 3 control circuit.
Action Taken When the DTC Sets
DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.
