Symptom Related Diagnostic Procedures

Possible Cause For Odors

- Odor from burned oil.
- Occurs mostly in engine compartment from a leak on the engine or transmission.
- Sulphurous odor from exhaust gas.
- From leak on the exhaust system.
- From exhaust gas entering passenger compartment e.g. while driving in reverse (by driving through an exhaust cloud from same vehicle).
- Fishy odor from coolant.
- From leak at cooling system of engine or of A/C system heater core.

NOTE: If fishy odor from front A/C system vents is detected also in recirculated air mode as well as in fresh air mode, check heater core of front heating A/C unit for proper seal.

- Odor from a scorched clutch
- Emanations from floor mats, subsequently installed decorative seat covers etc.
- Rotten moldy odor from plenum chamber.
- From accumulation and storing of various contaminants like leaves, tree needles etc. (e.g. in plenum chamber)
- From water which cannot flow out of the plenum chamber or fresh air intake housing.

NOTE: Check water drains of plenum chamber and of A/C system fresh air intake housing.

- Odor from front heating A/C unit (and/or rear).

NOTE: Odors e.g. originating in front heating and A/C unit can mainly be detected in fresh air mode as well as in recirculated air mode. If there is a complaint of odor at front heating A/C unit only in fresh air mode or recirculated air mode, the cause is not in the front heating A/C unit in most cases.

- If heater core is not sealed tightly, the odor may be of leaking coolant depending on temperature setting (air is not continuously flowing through heater core).
- From excessive water condensation in heating and A/C unit.

NOTE: Check condensation water drain of front heating A/C unit.

- From an old or severely soiled dust and pollen filter in front heating A/C unit.

NOTE: Check dust and pollen filter.

- From deposits on evaporator lamellae.

NOTE: Clean evaporator using Ultrasonic Cleaner VAS6189A.