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Asymmetric cooling (driver/passenger different temperature)

Q: How to fix Asymmetric cooling (driver/passenger different temperature) in BMW 3 Series (E90)?

Flush the heater thoroughly with pressurized water or replace the heater. Flushing is performed under the hood, disconnecting the hoses going to the bulkhead wall.

in BMW 3 Series (E90) (2005-2011)

Symptoms

Different temperature on both sides of the cabin

DTC error codes

No codes in INPA

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Technical diagnosis (Premium)

Recognized technical fault:

Auxiliary controller voltage instability detected

Technical analysis

Detailed analysis of HVAC controller operation parameters, CAN bus data readings, and diagnostic signal waveforms. Purchase PRO access or log in to read the full fault analysis.

Confirmed solution

Complete step-by-step repair procedure including module non-volatile memory reset, sensor calibration, and correct wiring routing. Unlock the full report to see the instruction.

Parts needed

Filters ferrite anti-interference / noise suppressor
Auxiliary starting battery (depending on cell status)

Workshop hacks

Important workshop tips for mechanics regarding bypasses without expensive control module replacement and manufacturer software service bulletins.

TSB / TPI service bulletins

TSB-24-HVAC-01TPI-2068943/2

A/C Technical Specifications

(F34) Gran Turismo

Refrigerant: R134a Amount (g): 550g Oil: PAG PAO 68 lub PAG ISO 46 b.d. Oil (ml): b.d.ml

(F30) Hybrid 3

Refrigerant: R134a Amount (g): 740g Oil: PAG PAO 68 lub PAG ISO 46 b.d. Oil (ml): b.d.ml

(F30/F31)

Refrigerant: R134a Amount (g): 550g Oil: PAG PAO 68 lub PAG ISO 46 b.d. Oil (ml): b.d.ml

See full specification

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Asymmetric cooling (driver/passenger different temperature)

Symptoms

DTC error codes

A/C Technical Specifications

Other problems in 3 Series (E90)

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