Hey, I am so confused but ill do my best to explain whast going on.

I am throwing CEL #3 (Map Sensor) So I looked up in the Service manual how to troubleshoot this Code.

I checked the voltage at the map sensor with the Key in accessory.

The Ground is hooked up good.
The Power wire is reading 5V (good)
The Signal wire is not reading **** (bad)

Then the Service manual says to check the voltage at the ECU.

The same results as above came.

THe service manual says to replace with a good known ECU and try again.

THE ECU IS STILL NOT PUTTING OUT THE CORRECT VOLTAGE FOR MY MAP SENSOR

What is wrong? What do i check now?

 

have you tried swapping map's?

 

The Signal wire is not an output. The ECU simply reads the voltage that is output form the MAP sensor. You either have a bad MAP sensor, or the signal wire form the MAP sensor to the ECU is compromised.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">have you tried swapping map's?</TD></TR></TABLE>
Yep, same problem.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jim Truett &raquo;</TD></TR><TR><TD CLASS="quote">The Signal wire is not an output. The ECU simply reads the voltage that is output form the MAP sensor. You either have a bad MAP sensor, or the signal wire form the MAP sensor to the ECU is compromised.</TD></TR></TABLE>
yeah this is true, but when the accessories are on, there should be 5V's reading at the Map sensor signal wire, and at the ECU.

Thanks for the replys

 

I assume you are referring to the white wire (D17). It should never have 5 volts present under normal conditions. With the engine running it should be ~ 1-1.5 volts with the throttle closed under vacuum, and ~ 4-4.5 volts at WOT. You should only see 5 volts on the yellow/green wire (D19). Have you checked the harness for continuity? It sounds like there may be a bad input card in your ECU. Swap the ECU out and let us know how it works.

 

This is where i got the assumption it should be reading 5V's.

I did swap the ECU and i am still having the same problems. I figured that i had a bad ECU but when i swapped it and nothing happened I got confused.

Thats why im posting

How do i check the harness for continuity?


So Heres what i have done...

***Swapped Map Sensor.
***Swapped ECU
***Checked continuity on the signal wire (the White one) from the ECU Plug to the Map Sensor and it was good

 

In the Troublehsooting above...

In the spot where i said "NO" today i prentended i said yes...

I tested the voltage from the signal wire to a ground with the Map Sensor Plugged in.

It read 3 Volts...

According to the diagram the next step is to replace the ECU....

WHICH I ALREADY DID...

I didnt do this test with the switched ECU, but I did the other test and it didnt work...


Any advice?

 

? ?

 

man its not even like i can take the car somewhere to have it worked on, Theres not a shop in 60 miles that knows hondata...

 

Have you checked the signal wire for continuity from the ecu to the sensor? Are you sure it's going to the correct location on the ecu?

 

yes and yes.

I have the pinout sheet for my ECU, and the wires are the same color so im pretty sure its the same wire. =0[

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by debogsr &raquo;</TD></TR><TR><TD CLASS="quote">yes and yes.

I have the pinout sheet for my ECU, and the wires are the same color so im pretty sure its the same wire. =0[</TD></TR></TABLE>
Have you checked it for continuity to ground?

 

to what ground? I have been testing the voltage of that wire by putting the positive on the signal wire and the negative on either the Green Map Sensor wire or something metal that wuold ground like my Manifold.

All three of the wires are continuous from the ECU to the Map Sensor. I tested this by reading the Resistance from one end to the other. In all three cases it was 0 ohms.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by debogsr &raquo;</TD></TR><TR><TD CLASS="quote">to what ground? </TD></TR></TABLE>
Negative battery terminal ground would be good.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by debogsr &raquo;</TD></TR><TR><TD CLASS="quote">
All three of the wires are continuous from the ECU to the Map Sensor. I tested this by reading the Resistance from one end to the other. In all three cases it was 0 ohms. </TD></TR></TABLE>
That's good, but it doesn't tell if the signal wire is shorted to ground.

 

alright ill try that today
thanks for the reply