The OBDI Honda Code of 3 refers to the Manifold Absolute Pressure sensor going bad in your Honda. Because your ECU no longer has an accurate reading of the amount of pressure entering your Honda engine, this problem can result in poor fuel economy and a rough idle.
Today we’ll be showing you how to service OBDI Map sensor found in a 1993 Acura Integra GS with the 1.8 liter non VTEC engine in it. We’ll also be showing you how to test these wires at the MAP sensor as well as at the ECU, and giving you a step by step guide on how to replace said MAP sensor as well.
To begin our how to service OBDI MAP Sensor guide, you will need to open your hood and disconnect the negative terminal to your battery. The replacement part number for this OBDI MAP sensor is 37830-PR3-003 and it can also be found under the Acura badge as 37830-PV1-000.
If you need to know how to service OBDI Map Sensor in your Honda, you’ve got to locate it first. Your Acura Integra MAP Sensor is located behind your intake manifold, between the hood bonnet and your motor.
Connected by a three pin weatherproof connector, you must locate and disconnect this MAP sensor before you begin to service it.
Locate and unplug your MAP sensor, and get your multimeter out so that you can begin testing your MAP sensor wiring. If you are not familiar with a multimeter or voltmeter, check out our primer here.
Unplug the MAP sensor and take a look at the MAP connector and the three wires you’ll be testing. If you need to test your OBDI MAP sensor and do not know how, here’s the section for you.
From left to right you will see the following colored wires and their respective locations on the OBDI ECU.
The yellow / red OBDI MAP sensor wire is the ECU pin D19, which represents VCC1 or Sensor voltage for your Manifold Absolute Pressure sensor. This wire turns yellow / green at the ECU and terminates at the final ECU plug D. For a complete OBDI Honda ECU Pinout, check here.
Using your multimeter, measure the voltage at this wire by backpinning the sensor connector with the MAP sensor connected. Now gently blow into the front of the MAP sensor to see if the voltage moves at all or if your MAP sensor even registers any voltage fluctuation. Do not blow into the MAP sensor using a air compressor, as it’s designed to only read 11 psi above atmospheric pressure.
The next wire is the green / white wire which is the middle wire on your MAP sensor connector. This is ECU pin D21 which is SG1 or the low reference ground signal to your MAP sensor. This wire at the ECU is green with a blue stripe if you are testing at the ECU. Remember to never use the power or ground from the ECU when testing wires or using your multimeter.
Backpin this wire with the red wire on the positive terminal of your battery and backpinning this wire with the black lead.
Lastly the power wire which is a switched voltage signal sent to the MAP sensor to power it. This wire is white at the MAP sensor and terminates at D17 of your OBDI Honda ECU. This wire should provide a switched power signal to your MAP sensor.
If your wiring is correct and everything checks out on your OBDI MAP Sensor connector, it would appear that our 3 MAP code is caused by the MAP sensor. Unplug your MAP sensor, undo the screw that mounts it and transfer the vacuum hose from your intake manifold to the new MAP sensor. Reconnect the new MAP sensor and secure it with the screw you just removed.
You are now done and know how to service OBDI MAP Sensor should your Honda sensor go bad. Have any questions or comments regarding this article? Leave them for us below!