My Personal p0108 Code and TPS Problem - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > My Personal p0108 Code and TPS Problem

Ring & Pinion's, Lockers, 4340 Axles, Install Kits, BaRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits Engo winches available at www.rockridge4wd.com! Free shipp

Reply
Unread 09-06-2014, 05:32 PM   #1
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
My Personal p0108 Code and TPS Problem

Hello, so for a while now I have been looking around to find why my car jumps to 1500 rpm on start up and after cleaning the tps and elec. greasing the tps and iac connections, nothing is different.

Along with the rpm jumping I am now getting a hard downshift while on the highway (which I have heard can be related to a bad TPS).

Ok so that's one off the list: Buy a new TPS (Kolak, we'll talk soon)

NOW, the p0108:
I have had no major side effects with it *knock on wood* but just to double check I erased with a bluetooth OBDII connector and Torque app it and it came back. I read about the diagnosis on to find out if it was the sensor or not and was a little confused, so here are my readings.

With the engine on, but not running, one of the outside connectors read 5.12v and the other side read 5.1v and the middle read 9v. With the connector plugged back in, engine running, and back-probing it, I couldn't get a great reading but it was some crazy number that bounced around 50v whether revving the engine or not. It could have just been that I am bad at back-probing and couldn't get a good connection.

So I should get a new TPS, but what should I do about the MAP Sensor? Ill add any info later if I forgot anything.

__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-06-2014, 09:48 PM   #2
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Bump
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-07-2014, 07:19 AM   #3
86cj74.2L
Web Wheeler
 
86cj74.2L's Avatar
2004 WJ 
 
Join Date: Jul 2006
Location: Stouchsburg, PA
Posts: 6,642
The P0108 is associated with bad wiring or sensor.

1 Check for any related TSBs. All Ignition on, engine not running.
With the DRBIII􏰃, read DTCs and record the related Freeze Frame data.
Start the engine.
With the DRBIII􏰃, read the MAP Sensor voltage. Is the voltage above 4.8 volts?
Yes → GoTo 2
No → Refer to the INTERMITTENT CONDITION Symptom (Diagnos- tic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5.
2 Turn the ignition off. All Disconnect the MAP Sensor harness connector.
Connect a jumper wire between the (K1) MAP Sensor Signal circuit and the (K4)
Sensor ground circuit in the Sensor harness connector.
Ignition on, engine not running.
With the DRBIII􏰃, monitor the MAP Sensor voltage. Is the voltage below 1.0 volt?
Yes → Replace the MAP Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No → GoTo 3
NOTE: Remove the jumper wire before continuing.
TEST ACTION
APPLICABILITY

3 Turn the ignition off. All Disconnect the PCM harness connectors.
Ignition on, engine not running.
Measure the voltage on the (K1) MAP Sensor Signal circuit at the MAP Sensor
harness connector.
Is the voltage above 5.2 volts?
Yes → Repair the short to voltage in the (K1) MAP Sensor Signal circuit. Perform POWERTRAIN VERIFICATION TEST VER - 5.
No → GoTo 4
4 Turn the ignition off. All Measure the resistance of the (K1) MAP Sensor Signal circuit from the MAP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Yes → GoTo 5
No→ Repair the open in the (K1) MAP Sensor Signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
5 Measure the resistance between the (K1) MAP Sensor Signal circuit and the (K7) All 5-volt Supply circuit at the MAP Sensor harness connector.
Is the resistance below 100 ohms?
Yes → Repair the short between the (K7) 5-volt Supply circuit and the (K1) MAP Sensor Signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5. No → GoTo 6
6 Measure the resistance of the (K4) Sensor ground circuit from the PCM harness All connector to the MAP Sensor harness connector.
Is the resistance below 100 ohms?
Yes → GoTo 7
No→ Repair the open in the (K4) Sensor ground circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
7 NOTE: Before continuing, check the PCM harness connector terminals for All corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay
particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
TEST ACTION
APPLICABILITY
86cj74.2L is online now   Reply With Quote
Unread 09-07-2014, 08:07 AM   #4
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
What did I just bump myself into Hahaha well that's the most detailed answer I've gotten so thank you very much, but there is one problem. Where do I get one these drbIII to use for a day? They run for thousands of dollars online.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-07-2014, 08:27 AM   #5
86cj74.2L
Web Wheeler
 
86cj74.2L's Avatar
2004 WJ 
 
Join Date: Jul 2006
Location: Stouchsburg, PA
Posts: 6,642
Quote:
Originally Posted by jbaldry
What did I just bump myself into Hahaha well that's the most detailed answer I've gotten so thank you very much, but there is one problem. Where do I get one these drbIII to use for a day? They run for thousands of dollars online.
Any scanner that reads live data will work. You should have one in your tool box anyway. Along with a temp gun and a few other things.
86cj74.2L is online now   Reply With Quote
Unread 09-07-2014, 11:09 AM   #6
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Quote:
Originally Posted by 86cj74.2L View Post

Any scanner that reads live data will work. You should have one in your tool box anyway. Along with a temp gun and a few other things.
Ok, could you name a more affordable scanner that you like?
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-07-2014, 12:14 PM   #7
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
This is a quote from Greasefingers here on the ZJ forum on how to diagnose the Map Sensor or Harness

"MAP Sensor Testing
Remove the connector at the MAP. There are three pins inside the connector (in a straight line). With the Key positioned to “On”and not start, you should see 5 volts across the outer two pins. This means that the PCM and wiring harness is good.

Reconnect the MAP sensor. Back-probe (with a paper clip) the center pin and connect the other end of the voltmeter to ground. With the ignition key On and the engine not running the voltage be 4 to 5 volts. Start the engine. The MAP should measure sometime 1 to 2 volts. Now open the throttle a bit and the voltage should increase with increasing rpms."

"If you are getting a constant 5 volts threw the center pin AND/OR you get no reading across the two outters, you have a bad ground." -GreenDean

Is being off by .12 and .1 volts a big deal? Or is it safe to say its my sensor.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-07-2014, 12:16 PM   #8
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Here is a link to where this conversation took place: http://www.jeepforum.com/forum/f13/m...-p0108-338673/
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-07-2014, 12:39 PM   #9
86cj74.2L
Web Wheeler
 
86cj74.2L's Avatar
2004 WJ 
 
Join Date: Jul 2006
Location: Stouchsburg, PA
Posts: 6,642
Quote:
Originally Posted by jbaldry
Ok, could you name a more affordable scanner that you like?
I have the Innova 3130 with the ABS upgrade.

But I do not remember if the scanner displays both the map volts as well as the psi measurement. Or just the psi measurement. But I think a ignition on and no running should show close to 5v and max vacuum close to 1v.
86cj74.2L is online now   Reply With Quote
Unread 09-07-2014, 02:02 PM   #10
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,098
Quote:
Originally Posted by jbaldry View Post
Here is a link to where this conversation took place: http://www.jeepforum.com/forum/f13/m...-p0108-338673/
Unfortunately for you, the references to pin numbers in that conversation applied to ZJs, not WJs. See the attached connector pinout.

On WJs, pin #1 is where the sensor signal leaves the sensor heading for the PCM MAP sensor input. Pin #2 is where the sensor ground connection is made; while pin #3 is where the 5V power supply voltage from the PCM connects to the sensor.

With the sensor unplugged and the ignition ON, there should be close to 5V measured between #3 and #2 with #3 being positive. This measurement tells whether the sensor is getting the correct power or not.

Edit: Back probing with the sensor plugged in and ignition ON, the voltage between #3 and #2 will again be about 5V, while the voltage between #2 and #1 (with #1 being positive) will also be about 5V. Of course this means the voltage between #3 and #1 will be essentially zero.

With the sensor plugged in and engine idling, the back probed voltage between #3 and #2 should still be close to 5V, the same as before. The signal voltage, that's the voltage between #1 (Edit: corrected typo, #3 replaced by #1) and #2 (#2 or any other available ground) should be between about 1.5V and 2.0V. Momentarily opening up the throttle should cause the signal voltage to momentarily jump up near to 5V.

Measured voltage differences of a few tenths are not significant.
clipboard01.jpg  
__________________
2001 WJ Limited with Quadra-Drive, Kenne Bell Supercharger, 3-inch Kolak exhaust, Stillen rotors (F/R) and MM pads, Addco sway bars (F/R).
rm2001wj is offline   Reply With Quote
Unread 09-07-2014, 11:19 PM   #11
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Quote:
Originally Posted by rm2001wj View Post
Unfortunately for you, the references to pin numbers in that conversation applied to ZJs, not WJs. See the attached connector pinout.

On WJs, pin #1 is where the sensor signal leaves the sensor heading for the PCM MAP sensor input. Pin #2 is where the sensor ground connection is made; while pin #3 is where the 5V power supply voltage from the PCM connects to the sensor.

With the sensor unplugged and the ignition ON, there should be close to 5V measured between #3 and #2 with #3 being positive. This measurement tells whether the sensor is getting the correct power or not.

Edit: Back probing with the sensor plugged in and ignition ON, the voltage between #3 and #2 will again be about 5V, while the voltage between #2 and #1 (with #1 being positive) will also be about 5V. Of course this means the voltage between #3 and #1 will be essentially zero.

With the sensor plugged in and engine idling, the back probed voltage between #3 and #2 should still be close to 5V, the same as before. The signal voltage, that's the voltage between #3 and #2 (#2 or any other available ground) should be between about 1.5V and 2.0V. Momentarily opening up the throttle should cause the signal voltage to momentarily jump up near to 5V.

Measured voltage differences of a few tenths are not significant.
Ok, I'll let you know what my test results are and maybe you can help me translate the results.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-10-2014, 02:39 PM   #12
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Ok, I'm heading out to run the voltage tests; should have the results in an hour or so. Lets hope I can figure out the back-probing to get some accurate results.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-10-2014, 03:35 PM   #13
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Here are my results:
With engine on and not running: connector unplugged the voltage between 3 and 2 with 3 being positive it reads 5.12 volts (so 5)
With the connector plugged back in and back probing, engine on but not running: voltage between 1 and 2 with 1 being positive is 4.72 volts (so 5)
With engine RUNNING and back probing: voltage between 1 and 2 with 1 being positive is 1.34 volts ( i used #2, the alternator and the valve cover as different grounds all yielding the same result)
Now the same 1 and 2 with 1 being positive and trying different grounds, I pressed on the throttle and it caused the voltage to drop down anywhere from .6 volts to 1.2 volts depending on how much throttle I gave it. Essentially giving it throttle = decrease in voltage
After pressing the throttle it settled right back into it 1.34 to 1.36 volts.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote
Unread 09-10-2014, 06:28 PM   #14
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,098
I see you overlooked my typo up above where #3 should have been #1.

The signal voltage dropping instead of rising when the throttle is opened is not a good sign. When the throttle is momentarily opened, it allows the manifold pressure to increase momentarily and the signal voltage should increase. It looks to me like the MAP sensor needs to be replaced.
rm2001wj is offline   Reply With Quote
Unread 09-10-2014, 06:48 PM   #15
jbaldry
Registered User
2000 WJ 
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 338
Well that's honestly great news! I would much rather have to replace the sensor rather than have to chase around wires. Thanks everybody for the help, I really appreciate it and I hope this helps others in the future.

I'll report back after I replace the sensor to confirm that it has been fixed.
__________________
2000 Jeep Grand Cherokee Limited, Quadradrive, 4.7 V8
Living life mod by mod
jbaldry is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.