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TPS signal gone to crap (orange signal wire problems)

10K views 33 replies 5 participants last post by  Ondonti 
#1 ·
so ive been having problems and I found that the signal wire from my tps (orange/blue) is getting like 4.58 volts and the power wire (violet/white) is getting its proper 5.0 volts.

working on tracing it back but this is pissing me off.

If anyone has had this problem before that would be cool to know about.

that signal wire should be zero when not plugged in to the tps connector right?
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I just traced it back to the engine bay harness so its a problem before the engine harness. I got 4.58 volts @ the grey 10 wire connector.
 
#28 ·
Well possibly it might, apparently there is a stray voltage issue which cannot be located by running Chryslers flow charts for TPS. The sensor ground is shared by 6 other sensors,any one of them that has a ground problem or a short could be feeding back thru the TPS circuit.
Continuity : Any circuit that shows a resistance reading because it is connected.
Official Definition : The term describing the characteristic of a circuit which
will conduct a current.
Open : A circuit that reads infinite resistance because it is not connected.
Official Definition : A circuit which does not provide a complete path for the
flow of current(no continuity)
I still have not been been told weather the Code 24 is TPS voltage high or TPS voltage low. Only the scan tool will tell you that.
When it comes to electrical diagnostics you cannot guess or assume. You have to follow a logical diagnostis sequence,that is why Chrysler enginners went thru the trouble of writing Step by Step diagnostic flow charts.You have to start at step 1 and follow the chart according to your results otherwise you are chasing your tail. The first step is knowing exactly what fault code you are diagnoising.
 
#29 ·
sorry but it was running both 24 high and 24 low codes.

This was BEFORE the TPS system totally failed.

Since there are 4.58 volts @ the wire IM sure the code is 24 high right now.

Sorry I dont have the scanner right now I returned it at the race track a few weeks ago and I think my buddy (bansheenut) is busy with it.
Id like to buy one though.
 
#30 ·
Code 24 TPS Voltage High
Ignition key off, disconnect TPS connector,inpect the connector for damage,
corrosion or terminal push out. Is the connector condition ok?
NO, repair as necessary
YES, Ignition key on, connect a jumper wire between the OR/DB and the
BK/LB wires. With the scanner read the TPS voltage.
Is the voltage below 1.0 volt?
YES, Replace the TPS
NO, Move the jumper wire to the OR/DB wire and ground. with the scanner
read TPS voltage,is the voltage below 1.0 volt?
YES, Repair the open BK/LB wire.
NO, Ignition Key off, disconnect the engine controller,inspect the connector.
Is the connector condition ok?
NO, Repair as necessary
YES, With an ohmmeter test the OR/DB wire for resistance.
Is the resistance below 10 ohms?
YES, Replace the engine controller
NO, Repair the open OR/DB wire

Checking Engine Controller Grounds and Power Circuits
Key off, disconnect engine controller connector, is the connector condition
ok?
NO, Repair as necessary
YES, With an ohmmeter probe cavity 5 in the engine controller(BK/WT)conn.
to ground.Is the resistance below 1.0 ohm?
NO, Repair the BK/WT wire for open to ground
YES, Probe cavity #'s 11 and 12. Is the resistance below 1.0 ohms?
NO, Repair that circuit for open to ground
YES, Controller grounds ok
Key On, With a voltmeter probe cavity 9(DB) in the engine controller conn.
NO, Repair the Open DB wire
YES, Test Passed

Controller Power Supplies
Term # 3 RD, Direct Battery Input
Term # 9 DB, Ign. Start/Run
Controller Power Outputs
Term # 6 VT/WT 5 Volt Supply
Term # 7 OR 8 Volt Supply
 
#31 ·
thanks alot for this help. Im a bit tired getting my race car together so i got a bit lost on the ground instructions. The first ones look really easy I just dont quite understand what "repair the open or/db wire means"

I think my brain will be working better saturday after I either go racing...or dont friday :p


Just wanting to know if "failure" mode will mean the engine behaves differently @ WOT
I know the engine will assume WOT based on MAP signals but I dont know if it actually uses the WOT fuel and ignition advance tables. Im guessing it would since WOT timing advance is probably more conservative then part throttle anyways.
 
#32 ·
When you turn on your Ohmmeter(Must be Digital)before it is Connected there will be a Number on the Screen that will probably be Flashing or it may read Open or Infinite,this is what you will see when you check a Wire or Circuit and it is Open. Also if the Resistance in the Wire/Circuit is Higher than the Scale you have the Meter set to it will read the same way.If your Meter has "Auto" it is Recommended you use this as the Scale will change Automatically. Just be sure you are Reading the Scale Correctly as to Ohms and Kilo Ohms.
If there is a Short a Wire(s) are touching each other,a ground or a voltage supply
If a Wire is Open it is broken,no longer making a complete circuit.
If a Wire is Shorted to Ground there is no Reistance(0,Not Open) in the Circuit and Amperage Flow Increases which usually results in a Blown Fuse or Fuseable Link.
If 2 wires are Shorted together depending on the Circuit you could be Feeding Power into a Non Powered Circuit or in the case of an Engine Controller it may see Voltage on a Circuit that is not supposed to be there and will Set a Fault Code for that Circuit because it is now Out of Range.
I feel that this is where your problem lies,that there is Stray Voltage being Fed into the TPS Signal Line from another source.
A Circuit that is Open creates another set of problems. Electricity is Extremely Lazy, it always looks for the Easiest Path to Ground. The problems occur when the Circuit that is Open is shared by other Circuits/Components,the Electricty looks for an Alternate Path to Ground and may cause another Circuit to be Powered even when it is off.
A few years back we had a Grand Cherokee that the Interior Lights were On and would not turn Off. Turns out that the Fuse for the Interior Lights was Blown(Open) and the Current found an Alternate Path around the Blown fuse and Headlamp Switch and back to the Interior Lamp Circuit keeping it Powered all the time.
If you are not Proficent with Electrical Diagnostics see if you can find someone to help you out to understand what you are testing, as Tedious as this is it may be benificial to have another mind there with you.
Please do not take that as an insult,not every Tech knows everything,I work with Techs who will be the first to tell you they do not understand enough to get involved with problems like these.
As Complicated as Vehicles have become even Dealerships have Techs that Specialize because the Training involved for a Certain System is Complex, Time Consuming and an Ongoing Process.It just happens that Electrical Diagnostics are my Strong Point.
Even the most Experianced Techs run into Problems that they cannot solve,that is why Chrysler has the "Star Hotline".
As far as Failure, the Vehicle will Run on a Fixed Program,and may run better than the vehicle did with the Problem Circuit.I do not know about WOT since that is also a Fixed Program in the Controller. As far as Throttle Position the Controller will probably use MAP and VSS to determine this.
 
#34 ·
I just finished replacing the wiring harness tonight and now the TPS problem is gone. My airbag warning light also did not turning on with this new harness so that might have been part of the problem.

I still have to tap into the harness to get the manual trans speed sensor working. No such thing as a manual trans v6 AA-body harness.

My tach isnt working either but I dont care because the care drives great again!
 
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