Metric Wrench Billings: What Do All Those Lights Mean on My Dashboard?

On most Mercedes and BMW’s the instrument panel is absolutely cluttered with warning indicator lights and buzzers. These lights are color-coordinated so that different colors indicate the severity of the potential problem. As you start the car, all of the lights should come on, and as the computer in your car verifies that each component is working properly, the light is turned off. You should only be concerned with lights that remain on for several minutes after the car has been started. Check engine lights can be tricky to repair, so a little help on your part could really save the mechanics at Metric Wrench some diagnostic time, and save you some money!

Treat check engine light as well as all dash lights work like traffic signals. A Red Warning light indicates an immediate danger. Pull over, turn off the car immediately and assess the problem. Symptoms that usually cause red warning lights are engine over-heating, low oil pressure, transmission over-heating, low battery voltage, and brake failure.

Red lights can also indicate a safety issue, so proceed with caution as you maneuver to stop the vehicle. Unfortunately, when the red light is illuminated the problem is at its peek. It can be a matter of seconds before permanent engine damage occurs.

Some common things to look for when a red light comes on are:

• Low anti-freeze, engine oil, and transmission fluid levels
• Low brake fluid
• Missing belts
• Faulty alternator that is not charging the battery or a bad battery
• Safety restraint systems, such as air bags

Yellow Warning lights, (Usually a check engine soon light) indicates "Proceed with caution." The onboard computer system has indicated a potential problem and is alerting the driver. This computer system resets and re-tests all sensors and indicators each time the car is started. The computer system is capable of correcting some minor abnormalities, but if the light continues to come on after multiple car starts, it is probably sensing something that would imply a visit to Metric Wrench is in order.

Some common things that may cause a yellow light (Service engine soon light) to come on, but will probably require an experienced technician at Metric Wrench to diagnose are:

• Anti-lock brake systems
• Emissions components
• Computer-related problems, such as faulty sensors

If you are driving your car and a yellow light comes on, ask yourself these questions:

1. Did you notice problems when starting the car? (Slower to start than normal, etc.)

2. Have you noticed a decrease in fuel mileage recently?

3. What is the over-all running condition of the car? Is the engine misfiring or not performing like normal? Are there any new noises from under the hood? Turn off the radio and listen closely as you drive the car.

4. Do you notice any odors, such as a rotten egg smell, or see visible smoke from the tailpipe or from under the hood?

Make sure to note the exact location and wording of the light that has been coming on, because Murphy's Law dictates that the light will suddenly not come on when you take it in to Metric Wrench.

In some cars, "engine" is the more serious red light, whereas others use "check engine light," which is a yellow caution light. If your mechanic THINKS you are seeing a yellow "check engine light," and your car is indicating a red "engine" danger light, this could be a costly mistake for both of you. Why? You could be having a serious over heating problem and the mechanic is assuming you are having a less serious caution light illuminating. Your mechanic then might give you the "green light" (no pun intended) to proceed with your out of town road trip with the kids. Yikes! So NOTICE the color of the light to give your mechanic the most accurate information.

Start your car and point to the light to ensure good communication of the problem. Intermittent dash warning lights can be a pain and hard to diagnose! Diagnosing the problem in some cases will require the light to be on while your mechanic performs the diagnostic test.

It’s a good idea to keep a "running condition and dash light" log in your car to help your mechanic pin point the root of the problem.

And one last note, it’s a good idea to know which warning lights should light up when the key is turned to the start position (the engine is not started). A warning NOT lighting up that should light up can indicate a problem as well. Most commonly the “Change Battery” light. If the change battery light does not come on when the key is in the start position, but the engine is off, may indicate a problem with the charging system.

AND the check engine light “Service Engine Soon” and “SRS” or “Airbag” light should always come on when the key is in the start position, but the engine is off. There is always the possibility the bulbs have been removed rather than a proper repair.

Resetting the Service Interval Indicator (SII) on Your BMW

20 Pin Socket Deletion

Model & Production Date:
E46 from 6/00
E39, E52, E53 from 9/00
For model year 2001 the E39, E46, and E53 will eliminate the 20 pin diagnostic connector from the engine compartment.

On 2001 3 Series and 5 Series vehicles without the diagnostic connector in the engine compartment, the SII reset tool can no longer be used. Instead, the SII can be reset with the trip odometer reset button in the instrument cluster, following the instructions listed below:

• The ignition key must be in the “O” (“off”) position.

• Press and hold the trip odometer button in the instrument cluster, and turn the ignition key to the “1” (accessory) position.

• Keep the button pressed for approximately 5 more seconds until any of the following words appear in the display: “Oil Service” or “Inspection”, with “Reset” or “Re”.

• Press the button again and hold for approximately 5 seconds until the words “Reset” or “Re” flash.

• While the display is flashing, press the button briefly to reset the Service Interval. After the display has shown the new interval, the following will appear in the display for approximately 2 seconds: “END SIA”.

The system can only be reset again after the vehicle has been driven approximately 50-75 miles (consumes at lease 2.5 gallons of fuel). If the display shows “Reset” or “Re” when resetting, the minimum driving distance has been fulfilled and the system can be reset again. It is possible to interrupt and end the reset procedure by changing the position of the ignition key.

Note: An alternate method to reset the SII is to use the OBD adapter harness (available under P/N 90 88 6 614 300, sent to all BMW centers as part of the Automatic Tool Shipment Program) together with the SII Reset Tool (available under pin 88 88 6 621 110). Fasten the Reset Tool to the OBD adapter harness, and then connect the harness to the OBD/diagnosis socket in the driver’s footwell. Reset the SII per usual procedure.