What is an IAC ?

Idle Air Control (IAC) Valve

OPERATION

The Idle Air Control (IAC) valve controls the engine idle speed and dashpot functions. The valve is located on the side of the throttle body. This valve allows the necessary amount of air, as determined by the Powertrain Control Module (PCM) and controlled by a duty cycle signal, to bypass the throttle plate in order to maintain the proper idle speed.

TESTING

Turn the ignition switch to the OFF position. Disengage the wiring harness connector from the IAC valve . Using an ohmmeter, measure the resistance between the terminals of the valve. NOTE: Due to the diode in the solenoid, place the ohmmeter positive lead on the VPWR terminal and the negative lead on the ISC terminal. If the resistance is not 7–13 ohms, replace the IAC valve.

Check Engine Code P0420

Code P0420 : Catalyst System Efficiency Below Threshold This code is set when the o2 sensor behind the catalytic converter sees a lower signal than the set parameters of the OBDII system. English : The Catalytic converter is no longer doing an efficient job and needs to be replaced. Symptoms : Check Engine Light On Drivability : Not affected Causes : 1) Age 2) Running rich caused by failing upstream o2 sensor or failing MAF 3) Fuel Injector Stuck Open Fix : Replace Catalytic Converter and test system

How do I compress the rear caliper piston on my '05 Ford Freestyle

This requires a special tool. You need to rotate the piston clockwise to compress it.

2005 Saturn ion No Start

Question: Saturn ion 2005 problem starting-every three or four starts, the lock symbol shows up and car will not start, panel, headlamps, acessories are operating, but starter seems locked out. After 4 minute wait, it usually starts. Why? Optional Information: 2005 Saturn 10n 3 2.2L4 Answer: This is a common issue with this model. You will need to have the ignition switch replaced and that will take care of it. As of today there is not a recall issued but save your receipt so you can get reimbursed if they do decide to issue a recall.

Crank Seal Is Still Leaking How Do I fix it ??

I have a 1990 Mitsubishi Mighty Max, 3.0 V6. I have an oil leak at the front crank pulley. I have replaced the crank seal and still have a leak after the motor warms up. Do you have any ideas of the problem I am facing.

What you will need is a speedy sleeve. When the crank seal wears a groove in the crank you need to install a speedy sleeve on teh crank so the new seal has a new un-grooved surface to seal itself against. You should be able to purchase one at your local auto parts distributor.

Automotive Questions and Answers

You will fine there are many different places around the net that offer up answers to questions for example yahoo answers, ask patty, and the list goes on and on. When you have an automotive related question you need to find a place that can give you the answer you need. This is why having your questions answered by professional mechanics is important especially when time and money are involved. We have found a few places that have met this criteria, actually respond to your questions with accurate and sound knowledge. All you need to do is click the button above or go directly to http://www.freeautomechanic.com/ or http://www.freeautoanswers.com/. We have found them to both be accurate and professional. If you have found any others that you would recommend please comment below.

Automotive Air Conditioning

No air coming from air conditioning vents Check the air conditioner fuse and replace as necessary. Air conditioner system discharged. Have the system evacuated, charged and leak tested by an MVAC certified technician, utilizing approved recovery/recycling equipment. Repair as necessary. Air conditioner low pressure switch defective. Replace switch. Air conditioner fan resistor pack defective. Replace resistor pack. Loose connection, broken wiring or defective air conditioner relay in air conditioning electrical circuit. Repair wiring or replace relay as necessary. Air Conditioner blows warm air Air conditioner system is discharged. Have the system evacuated, charged and leak tested by an MVAC certified technician, utilizing approved recovery/recycling equipment. Repair as necessary. Air conditioner compressor clutch not engaging. Check compressor clutch wiring, electrical connections and compressor clutch, and repair or replace as necessary. Water collects on the interior floor when the air conditioner is used Air conditioner evaporator drain hose is blocked. Clear the drain hose where it exits the passenger compartment. Air conditioner evaporator drain hose is disconnected. Secure the drain hose to the evaporator drainage tray under the dashboard. Air conditioner has a moldy smell when used The air conditioner evaporator drain hose is blocked or partially restricted, allowing condensation to build up around the evaporator and drainage tray. Clear the drain hose where it exits the passenger compartment

Scan Tool Codes | Trouble Codes

Here is how to scan for codes without a Scan Tool. Follow the Links below to the right category and follow the instructions. '92 - '95 Honda OBD I Codes '91 - '93 Saturn OBD I Codes '93 - '95 Ford Probe OBD I Codes GM OBD I Codes Ford OBD I Codes Chrysler OBD I Codes Full list of OBD II OBD II Tuner Codes Hyundai Specific Codes Isuzu Specific Codes V W Specific Codes OBD II Codes require a Scan Tool , Once you have the code you can refer to the list below for a description of each code. http://www.freeautomechanic.com/scantoolslist.html P0100 - P0199 P0200 - P0299 P0300 - P0399 P0400 - P0499 P0500 - P0599 P0600 - P0699 P0700 - P0799 P0800 - P0899 P0900 - P0999 P1000 - P1099 P1100 - P1199 P1200 - P1299 P1300 - P1399 P1400 - P1499 P1500 - P1599 P1600 - P1699 P1700 - P1799 P1800 - P1899 P2000 - P3000

Secondary Air Injection Code P1411

OPERATION The Secondary Air Injection (AIR) system is an electronically controlled system. The system diverts secondary air upstream to the exhaust manifold check valve or downstream to the rear section check valve and catalyst. The system will also dump secondary air into the atmosphere during some operating modes. TESTING Normally Closed Air Bypass Valve Functional Test Disconnect the air supply hose at the valve. Run the engine to normal operating temperature. Disconnect the vacuum line and make sure vacuum is present. If no vacuum is present, remove or bypass any restrictors or delay valves in the vacuum line. Run the engine at 1500 rpm with the vacuum line connected. Air pump supply air should be heard and felt at the valve outlet. With the engine still at 1500 rpm, disconnect the vacuum line. Air at the outlet should shut off or dramatically decrease. Air pump supply air should now be felt or heard at the silencer ports. If the valve doesn't pass each of these tests, replace it. Normally Open Air Bypass Valve Functional Test Disconnect the air supply hose at the valve. Run the engine to normal operating temperature. Disconnect the vacuum lines from the valve. Run the engine at 1500 rpm with the vacuum lines disconnected. Air pump supply air should be heard and felt at the valve outlet. Shut off the engine. Using a spare length of vacuum hose, connect the vacuum nipple of the valve to direct manifold vacuum. Run the engine at 1500 rpm. Air at the outlet should shut off or dramatically decrease. Air pump supply air should now be felt or heard at the silencer ports. With the engine still in this mode, cap the vacuum vent. Accelerate the engine to 2,000 rpm and suddenly release the throttle. A momentary interruption of air pump supply air should be felt at the valve outlet. If the valve doesn't pass each of these tests, replace it. Reconnect all lines. Air Control Valve Functional Test Run the engine to normal operating temperature, then increase the speed to 1500 rpm. Disconnect the air supply hose at the valve inlet and verify that there is airflow present. Reconnect the air supply hose. Disconnect both air supply hoses. Disconnect the vacuum hose from the valve. With the engine running at 1500 rpm, airflow should be felt and heard at the outlet on the side of the valve, with no airflow heard or felt at the outlet opposite the vacuum nipple. Shut off the engine. Using a spare piece of vacuum hose, connect direct manifold vacuum to the valve's vacuum fitting. Airflow should be heard and felt at the outlet opposite the vacuum nipple, and no airflow should be present at the other outlet. If the valve is not functioning properly, replace it. Air Supply Pump Functional Check Check and, if necessary, adjust the belt tension. Press at the mid-point of the belt's longest straight run. You should be able to depress the belt about 1⁄2 in. (13mm) at most. Run the engine to normal operating temperature and let it idle. Disconnect the air supply hose from the bypass control valve. If the pump is operating properly, airflow should be felt at the pump outlet. The flow should increase as you increase the engine speed. The pump is not serviceable and should be replaced if it is not functioning properly.

BELTS AND HOSES

How long do the belts in my car typically last?

Your belts drive critical systems of your car, including your alternator which recharges your battery, your water pump which keeps your engine cool, your air conditioner which keeps you cool, and your power steering pump. If a belt breaks, the effects can range from the simple inconvenience of not having your air conditioning to leaving you stranded in traffic to overheating and ruining your engine.V-belts will typically last three years or 30,000 miles. Serpentine belts will go farther, lasting five years or 50,000 miles. Belts will sometimes show visible signs of age before they break, including cracking, fraying, and glazing. Modern belts often show no visible signs of deterioration before they break, however.

How often should the hoses be replaced?

Like belts, hoses harden, split, or soften with age. Sometimes the aging is visible. Often, however, there are no outward signs of problems before a hose bursts or starts leaking. According to one study, internal corrosion caused by electrochemical reactions in the cooling system is the leading cause of hose failure. Hose manufacturers recommend replacing hoses every four years.

How often should I replace the timing belt in my car?

Many of the cars on the road today have timing belts. They keep the valves and pistons in your car in synch. These belts take the place of a timing chain. The advantage is that they are lighter and more fuel efficient. The drawback is that they wear out quicker. Like a fan belt, a timing belt needs to be replaced before it breaks. The timing belt needs to be replaced every 50,000-60,000 miles on most cars, but the exact interval depends on the make and model of your car.If you wait too long and your belt breaks while you are driving down the road, your engine loses its coordination. This can have horrible results. Your pistons may hit your valves, causing major damage to the head of your engine. It is common for repair bills to run $1000 to $2000 for this problem. Replacing your timing belt is one maintenance item you never want to skip.