Absolute pressure sensor CEL
05-17-2005, 08:00 PM
#1
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Thread Starter
Join Date: May 2005
Posts: 51
Absolute pressure sensor CEL
First off hello to all. This is my first Maxima so I've been scanning this board trying to soak up all the info I can.
The car is a 96 with 140000 on the clock. It was given to me by a friend who just got another car and did not want to try and sell the Maxima, so lucky me. He has had the car since 105k miles and just preformed the basics ie oil changes and who knows what was done before that. The car ran pretty good when first started but after a few minutes it would sputter and hesitate on acceleration. A couple of times it would not start on the first couple attempts, it almost seemed like it was fuel starved. Also the idle seems a bit low while in drive about 600rpm. In park it goes up to about 750. So far I've done the fluid changes, tb cleaning, icv cleaning, new air filter, fuel pump. New spark plugs are coming soon.
Here's the problem. When I got the car the CEL was on, so I pulled the codes and got P0105 and P0325. These codes translate to the absolute pressure sensor and the knock sensor. A quick trip to the bone yard and I've got a used absolute pressure sensor and knock sensor. I replace the pressure sensor and the sputtering and hesitation is gone. I mean it pulls like a bat out of hell. I swap the knock sensor as the one on the my car is cracked. No difference noticed there. Anyway I clear the codes and restart the engine. You guessed it both codes returned within seconds.
So what's my problem? My guess is that somewhere in or around the pressure sensor circuit is causing the CEL and knock sensor to set off. What else should I be looking at dealing with the absolute pressure sensor. Thanks
The car is a 96 with 140000 on the clock. It was given to me by a friend who just got another car and did not want to try and sell the Maxima, so lucky me. He has had the car since 105k miles and just preformed the basics ie oil changes and who knows what was done before that. The car ran pretty good when first started but after a few minutes it would sputter and hesitate on acceleration. A couple of times it would not start on the first couple attempts, it almost seemed like it was fuel starved. Also the idle seems a bit low while in drive about 600rpm. In park it goes up to about 750. So far I've done the fluid changes, tb cleaning, icv cleaning, new air filter, fuel pump. New spark plugs are coming soon.
Here's the problem. When I got the car the CEL was on, so I pulled the codes and got P0105 and P0325. These codes translate to the absolute pressure sensor and the knock sensor. A quick trip to the bone yard and I've got a used absolute pressure sensor and knock sensor. I replace the pressure sensor and the sputtering and hesitation is gone. I mean it pulls like a bat out of hell. I swap the knock sensor as the one on the my car is cracked. No difference noticed there. Anyway I clear the codes and restart the engine. You guessed it both codes returned within seconds.
So what's my problem? My guess is that somewhere in or around the pressure sensor circuit is causing the CEL and knock sensor to set off. What else should I be looking at dealing with the absolute pressure sensor. Thanks
05-17-2005, 08:27 PM
#2
quaker - If you don't have a Haynes - its time to get one... but here is some info to get you started (from the FSM).
1. Check the vacuum line into the absolute pressure (Boost) sensor from the MAP/Baro Solenoid. Make sure the hose is connected, not clogged/torn/etc.
2. Check that the vacuum line to the MAP/Baro solenoid from the intake manifold is intact and that there is vacuum.
3. Check the absolute pressure sensor harness for voltage and ground as follows:
a. Make sure ignition is off
b. Disconnect the absolute pressure sensor harness - orient it such that the clip is pointed up when you look into the harness at the pins. The layout with the clip on the top side is pins [1 2 3].
c. Turn the ignition to on
d. Check for approx. 5V between terminal 3 and an engine ground.
e. Turn ignition off
f. Check for continuity (ground) between pin 1 and an engine ground.
Thats the basic stuff. If all that looks ok - then you'll have to dig deeper - and a Haynes or FSM will be your best bet. If you don't have access to either lmk via a PM.
1. Check the vacuum line into the absolute pressure (Boost) sensor from the MAP/Baro Solenoid. Make sure the hose is connected, not clogged/torn/etc.
2. Check that the vacuum line to the MAP/Baro solenoid from the intake manifold is intact and that there is vacuum.
3. Check the absolute pressure sensor harness for voltage and ground as follows:
a. Make sure ignition is off
b. Disconnect the absolute pressure sensor harness - orient it such that the clip is pointed up when you look into the harness at the pins. The layout with the clip on the top side is pins [1 2 3].
c. Turn the ignition to on
d. Check for approx. 5V between terminal 3 and an engine ground.
e. Turn ignition off
f. Check for continuity (ground) between pin 1 and an engine ground.
Thats the basic stuff. If all that looks ok - then you'll have to dig deeper - and a Haynes or FSM will be your best bet. If you don't have access to either lmk via a PM.
05-17-2005, 08:57 PM
#3
Senior Member
Join Date: Jan 2005
Posts: 1,108
Originally Posted by quaker
A quick trip to the bone yard and I've got a used absolute pressure sensor and knock sensor. I replace the pressure sensor and the sputtering and hesitation is gone. I mean it pulls like a bat out of hell. I swap the knock sensor as the one on the my car is cracked. No difference noticed there. Anyway I clear the codes and restart the engine. You guessed it both codes returned within seconds.
05-19-2005, 06:29 PM
#5
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Thread Starter
Join Date: May 2005
Posts: 51
The knock sensor checked out at 590-ohms. So I guess its ok.
The absolute pressure sensor harness test shows continunity between pin 1 and ground. Pin 3 and ground yields no steady results. What I mean by that is that my meter shows .490 volts, half a second later .390v and half a second later .520v. Maybe not those numbers exactly but close. These results are no where near the 5v I should be seeing.
So what does this mean? Where should I look now? The vehicle seems to run so well its hard to believe anything is wrong with her.
The absolute pressure sensor harness test shows continunity between pin 1 and ground. Pin 3 and ground yields no steady results. What I mean by that is that my meter shows .490 volts, half a second later .390v and half a second later .520v. Maybe not those numbers exactly but close. These results are no where near the 5v I should be seeing.
So what does this mean? Where should I look now? The vehicle seems to run so well its hard to believe anything is wrong with her.
05-20-2005, 08:24 AM
#6
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Posts: n/a
I got the same Code for the APS. Picked one up at a junk yard for like 5 bucks...Yanked the plastic hose off, mounted and connected it and the code dissapeared. Haynes Manual all the way! It's well worth the $18 and it will save your pockets in the long run. Good luck with the Max.
05-21-2005, 05:37 PM
#7
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Thread Starter
Join Date: May 2005
Posts: 51
As I posted above I was having sputtering and hesitaion issues with the old APS but the new one cleared that up. Also my knock sensor code has gone away.
My problem is that now when I clear all codes via my actron scan tool the CEL will stay dark but when I ask the tool to read codes it shows P0105, MAP/BARO circuit malfunction. The CEL will eventually come on again after the first restart. It almost seems as though something is disconnected because the tool shoots the code before even the the engine is started.
BTW What should the manifold pressure for our cars be? Using the scan tool while driving it showed MAP to be .3 hg. If that makes since to anybody. It never moved from this number.
Oh yeah I picked up the map/baro solenoid valve switches from the bone yard. I'll pop them on tomorrow and see what happens.
Any and all help welcome.
My problem is that now when I clear all codes via my actron scan tool the CEL will stay dark but when I ask the tool to read codes it shows P0105, MAP/BARO circuit malfunction. The CEL will eventually come on again after the first restart. It almost seems as though something is disconnected because the tool shoots the code before even the the engine is started.
BTW What should the manifold pressure for our cars be? Using the scan tool while driving it showed MAP to be .3 hg. If that makes since to anybody. It never moved from this number.
Oh yeah I picked up the map/baro solenoid valve switches from the bone yard. I'll pop them on tomorrow and see what happens.
Any and all help welcome.
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