Alfa Romeo1998–2001

166 2.0: Common faults & known problems

Common faults & known problems

9 known faults documented in workshop bulletins. Of these, five concern the engine and fuel system and one the brakes. Symptoms, causes, repair steps and part numbers are shown where supplied.

Technical specifications

Engine & fuel system

5 documented faults — symptoms, causes and workshop fixes.

Idle speed surges

Throttle valve not closing correctly due to build up of deposits in throttle body. Fix: clean and lubricate.

Overview

Affects: All models.
Remedy: Clean & lubricate

Symptoms

Engine jerking. Poor throttle response.

Repair steps

Remove throttle body intake pipe.
Clean deposits from inner wall.
Actuate throttle valve manually 3 to 5 times.
Inspect throttle body for any remaining contamination.
If necessary clean again.
Fit throttle body intake pipe.
Check idle speed.

Data: Motorwise Workshop. Bulletin 1.

Engine misfire

Water/oil ingress into spark plug orifice. Fix: clean and lubricate.

Overview

Affects: All models.
Remedy: Clean & lubricate

Symptoms

Engine malfunction indicator lamp (MIL) illuminated. Poor cold starting. Poor engine running.

Repair steps

Clean ignition coil and spark plug orifice.
Check spark plugs for insulator damage or arcing.
Check cylinder head cover for leaks.

Data: Motorwise Workshop. Bulletin 4.

Failure to start

Overview

Affects: All models.

Symptoms

Failure to start when engine is hot. Trouble code stored in engine control module (ECM) fault memory.

Cause

Faulty crankshaft position (CKP) sensor.

Repair

Replace crankshaft position (CKP) sensor.
Access engine control module (ECM) fault memory and erase trouble codes.

Data: Motorwise Workshop. Bulletin 7.

Engine malfunction indicator lamp (MIL) illuminated

Affects All models with petrol engines.P0325P1325

Symptoms

Trouble codes stored: P0325, P1325.

Cause

Knock sensor (KS) fault.

Repair

Check wiring connector and resistance of KS. Replace parts as necessary.

Data: Motorwise Workshop. Bulletin 8.

Knocking noise from engine compartment with engine idling

Overview

Affects: All models.
Remedy: Fit new part
Parts: 2 parts

Cause

Balancer shaft belt tensioner faulty.

Repair

Fit new balancer shaft belt tensioner.
Fit new balancer shaft belt.

Parts2 parts

Parts listed in the bulletin
Part	Part number	Qty
Balancer shaft belt	55221254	1
Balancer shaft belt tensioner	55221253	1

Data: Motorwise Workshop. Bulletin 9.

Brakes

1 documented fault — symptoms, causes and workshop fixes.

Squeaking noise from rear brakes

Affects All models.

Cause

Handbrake cable sticking due to internal damage/corrosion.

Repair

Replace both handbrake cables.

Data: Motorwise Workshop. Bulletin 6.

Air conditioning & heating

1 documented fault — symptoms, causes and workshop fixes.

Irregular operation of climate control

AC/heater air mix flap motor wiring trapped by engine bay fuse box/relay plate.

Overview

Affects: All models, →11/00

Symptoms

Fault 'air conditioning faulty, contact the Service Centre' displayed on digital multifunction display.

Repair steps

Check air mix flap motor wiring for damage.
If wiring insulation damaged, repair with tape.
Re-route wiring round left-hand end of fuse box/relay plate and secure to wiring harness clips.

Data: Motorwise Workshop. Bulletin 2.

Body & trim

1 documented fault — symptoms, causes and workshop fixes.

Bonnet not opening or closing correctly

Affects All models.Clean & lubricate

Cause

Bonnet catch seized.

Repair

Clean and lubricate bonnet catch.

Data: Motorwise Workshop. Bulletin 3.

Wipers & visibility

1 documented fault — symptoms, causes and workshop fixes.

Noise from lower windscreen area

Overview

Affects: All models.
Remedy: Clean & lubricate

Cause

Dry contact surfaces on front suspension upper arm bushes.

Front suspension upper arm bushes worn.

Repair

Check front suspension upper arm bushes for excessive play.
Replace or lubricate front suspension upper arm bushes as necessary.

Data: Motorwise Workshop. Bulletin 5.

Glossary

Technical terms used in this guide.

MIL: Malfunction indicator lamp — the engine warning light on the dashboard
ECM: Engine control module — the electronic unit that manages the engine
Trouble Codes: Standardised fault codes stored by the engine control module, read with a diagnostic tool
CKP: Crankshaft position sensor — tells the engine control module where the crankshaft is in its rotation
KS: Knock sensor — listens for engine knock so the engine control module can retard the timing
AC/Heater: The heating and air-conditioning system
Control Module: A control unit for one of the vehicle's systems (engine, gearbox, brakes, body, and so on)
Crankshaft Position: Where the crankshaft is in its rotation — used for ignition and injection timing
Fault Memory: The list of stored trouble codes in a control module
Relay: An electrically operated switch
Trouble Code: A standardised fault code stored by a control module, read with a diagnostic tool
Wiring Harness: The bundled cables that carry power and signals around the vehicle
Bushes: Rubber mountings that let a suspension or body joint move without metal-to-metal contact

Frequently asked questions

What are the common faults with the Alfa Romeo 166 2.0?

This guide contains nine workshop bulletins for the Alfa Romeo 166 2.0. Of these, five concern the engine and fuel system and one the brakes. Symptoms, causes, repair steps and part numbers are shown where supplied.

Does every Alfa Romeo 166 2.0 have these faults?

No. These are patterns documented across the model by workshops, not predictions for an individual vehicle. Where a fault applies only to certain vehicles or VIN ranges, that is listed with the fault.

Can I check for Alfa Romeo 166 2.0 faults myself?

Many of them. The documented symptoms can be seen, heard or felt during a test drive.