This article will help you to diagnose a BAD manifold absolute pressure (MAP) sensor (and DTC P0106, P0107, P0108, P01107) on your 3.2L 98-99 Isuzu Amigo, Rodeo, Trooper or Honda Passport.
All that you'll need, to successfully accomplish the three tests presented in this article is a multimeter. No Scan Tool is needed.
To help you navigate this article a little easier, here are its contents at a glance:
- Important Tips And Suggestions.
- Symptoms Of A BAD MAP Sensor.
- How Does The MAP Sensor Work?
- TEST 1: Checking The MAP Signal.
- TEST 2: Checking The MAP Sensor's Ground Circuit.
- TEST 3: Checking The MAP Sensor's Ground Circuit.
- MAP Sensor Code Won't Go Away.
Important Tips And Suggestions
TIP 1: All three wires coming out of the MAP sensor on your 3.2L Isuzu Amigo, Rodeo, Trooper (or Honda Passport) end up at the PCM (Powertrain Control Module = Fuel Injection Computer). So, be careful not to short these wires out when testing them.
TIP 2: The testing instructions call for the use of a vacuum pump. You can rent one (for free) at your local AutoZone or O'Reilly Auto Parts (if you live in the US and are near one). You can also use the good ole' lungs, but it won't be the most accurate (it works, but I don't recommend it).
TIP 3: You don't need to use a scan tool to test the MAP sensor. The testing instructions call for a multimeter. You can use a digital or an analog multimeter. Both will work.
Symptoms Of A BAD MAP Sensor
You'll have the CHECK ENGINE LIGHT on, for sure, on your instrument cluster and one of several of the following symptoms:
TPS diagnostic trouble codes P0106, P0107, P0108, P01107 stored in the vehicle's computer's memory and lighting up the check engine light.
Really BAD gas mileage. You know that it's not the price of gasoline that has you thinking that your Isuzu 3.2L (or 3.2L Honda Passport) is costing you more at the pump.
No power and/or hesitation as you accelerate the vehicle. Idle is not even.
How Does The MAP Sensor Work?
The manifold absolute pressure sensor's job is to measure the intake manifold's vacuum. In a nutshell, this is how the MAP sensor works:
When you turn the Key to the On position and then start the engine, the MAP sensor gets power thru' the wire labeled with the letter C. This power is in the form of 5 Volts.
ground is provided to the MAP sensor by the fuel injection computer thru' the circuit labeled with the letter A.
Now, as the engine idles, the pistons are creating vacuum inside the intake manifold (as they travel downwards in their stroke).
So then, when you accelerate the engine, the pistons come up and down even faster which creates more vacuum which is immediately measured by the MAP sensor. This info is then sent to the fuel injection computer thru' the wire labeled with the letter B.
So, no matter how much the engine revs up or decelerates, this will always cause a change in the intake manifold's vacuum and this vacuum changes are always relayed to the computer.
The Fuel Injection Computer uses this info (that the MAP sensor provides) to control fuel injection, Ignition Advance and host of other things to keep your engine running smoothly.