12223 Woodruff Ave, Downey CA 90241
Fine German Car Repair since 1978

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The Computer in  your Car


The "Computer" in Your Car Doesn't Have a Screen, a keyboard, or a Disk Drive --- but It's Got Lots of Connections.

Your car's on-board computer doesn't look anything like the kind that's used on a desktop. The "computer" is a small box called an ECM (Electronic Control Module), often mounted behind the glove box or in the engine compartment. The ECM controls all the essentials of engine operation: spark timing, fuel delivery, emissions, and in some cases even the air conditioning or the automatic transmission. Keeping all those systems in tip-top shape is no simple job; it requires complex test equipment and advanced diagnostic skills.

The computer continuously receives electrical signals from sensors and input devices, located in and around the engine. It analyzes this information and sends a stream of control signals to valves, controllers and other output devices, to balance the requirements of power, fuel economy and emission control. Some of the most common devices are shown in this brochure. Every engine, every car and every computer system is different -- but all the sensors, all the output devices, must be in perfect "sync" for the car to run properly.

No system is foolproof.  When problems develop, the malfunctioning parts must be replaced or adjusted. Otherwise the car won't run right, the gas mileage will be poor, and the car won't pass an emissions inspection. Only a qualified technician, with the right diagnostic equipment and technical data, can find out what's wrong and restore your car to original performance specifications.

Watch For These Warning Signs That Tell You Your Vehicle Needs Service

  • "Check Engine" or "Service Engine" light on

  • "Rotten egg" smell from the exhaust

  • Rough running or stalling

  • Engine knocking or pinging

  • Unstable, surging, or high idle

  • Lack of power

  • Poor gas mileage

  • Engine runs on after turning key off

The Professional Difference

The old-fashioned tune-up used to be done "by ear", but this isn't possible with computer-controlled engines A complete diagnostic check, followed by professional service, should be performed at factory-recommended intervals, or whenever your car shows any of the above warning signs. Our expert technicians can:

  • Test idle speed, throttle response, engine temperature, fuel system pressure, manifold vacuum, exhaust emission levels
  • Tap in and read the signals being sent between the computer, its sensors, and the output devices
  • Retrieve and investigate any "trouble codes" stored in the engine's computer, indicating that something is wrong or out of spec.
  • Repair or replace any malfunctioning parts; perform scheduled replacements or service as recommended by car manufacturer
  • Restore your car to original performance specifications, reliability and emission control requirements



(562) 803-4319

Westwerk Porsche/Audi/BMW/ Mini and Mercedes Repair
12223 Woodruff Ave.
Downey, Ca    90241
1(562) 803-4319