Determining Malfunction If Deviation From Specified Value

WARNING: This page is about a different variant/trim than selected.

The requested cooling output is not reached. Refer to COOLING OUTPUT, CHECKING, VEHICLES WITH MANUAL CLIMATE CONTROL SYSTEM or COOLING OUTPUT, CHECKING, VEHICLES WITH AUTOMATIC CLIMATE CONTROL SYSTEM .

NOTE:

This Service Information only outlines the testing procedure. Perform the detailed test for this heating and A/C system function as described in Guided Fault Finding. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function (for the Climatronic Control Module -J255-).

If a specified value is not reached, this may have various causes:

-- Determine the cause using the Vehicle Diagnostic Tester in the"Guided Fault Finding" function (for the Climatronic Control Module -J255-).

Possible causes for the deviation from specified value:

Dirty radiator or A/C system condenser.
Retrofitted components on or in the front end.
Malfunction in the activation or function of the Radiator Fan -V7- /Radiator Fan -V177-.
Malfunction in the coolant circuit; the coolant gets too hot.
Malfunction in the activation of the A/C Compressor Regulator Valve -N280- by the Climatronic Control Module -J255-.
Requests for switching off the activation of the A/C Compressor Regulator Valve -N280- transmitted to the Climatronic Control Module -J255- by other control modules.
Fault in the function of the A/C Compressor Regulator Valve -N280-.
Malfunction in the refrigerant circuit or A/C compressor.

If a malfunction was detected in the refrigerant circuit by the"Guided Fault Finding" :

-- The necessary work procedures may only be performed by qualified personnel. If this is not possible, bring the vehicle to a workshop that has the necessary tools and in which the work can be performed by qualified personnel. Refer to A/C SYSTEM, GENERAL INFORMATION and LAWS AND REGULATIONS . Bring the detected problems to the attention of the workshop.