Open the control box, disconnect the lower solenoid valve vacuum hose from the quad coupler and connect the vacuum pump.
Disconnect the #21 solenoid valve vacuum hose from the manifold and connect a pressure gauge.
Start the engine.
Attention: the temperature of the cooler must be below 70°C.
Create a vacuum.
If vacuum is visible on the pressure gauge, then A), otherwise B).
A) Warm up the engine to normal operating temperature (fan should turn on).
Create a vacuum in neutral or PARK.
If the solenoid valve holds vacuum, then A1), otherwise В1).
A1) Shift into D3 or D4 and apply vacuum.
If the gauge does not indicate vacuum, refer to the control module input diagnostics section, otherwise check the vacuum lines for damage, disconnections, or blockages.
IN 1) Disconnect the 8-pin connector from the control box. Measure the voltage between yellow/white (+) and black (-) conclusions of the main harness. If there is voltage, refer to the control module input diagnostics section, otherwise replace the solenoid valve.
B) Disconnect the 8-pin connector from the control box. Measure the voltage between yellow/white (+) and black (-) conclusions of the main harness. If there is voltage, replace the valve, otherwise measure the voltage between the yellow / white (+) output and grounding. If there is voltage, repair the break in the black wire between the control box and point G7, if not, check for a break in the yellow / white wire between the control box and terminal 19 of the control unit. If the wire is OK, refer to the diagnostics section.