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Crankshaft Position Sensor Reset

164K views 43 replies 17 participants last post by  Hacker777 
#1 ·
Replaced CPS, now it idles rough, rpm's bounce around. Original problem, engines shuts down while driving.
Need to reset and have no instructions on How To Reset. Any help would be greatly appreciated.

Thanks in advance,
 
#8 ·
Ooops,

1999, Wrangler Sport, 4.0L, Auto, OK so you don't reset the CPS, What will cause the rough idle after installation of new Crankshaft Position Sensor, rpm's jumping around. I pulled the gnd. cable off for approx. 15 sec, will redo with more time disconnected. maybe try the replacing the cam sensor. New Plugs (E3) New Wires, New Battery as of now. If all else fails then try to get a code check as mention above.

Thankssss
 
#9 ·
Ooops,

I pulled the gnd. cable off for approx. 15 sec, will redo with more time disconnected.

Thanks
Did you just disconnect it or did you disco it and hold it to the positive terminal for those 15 sec's? (that's what you need to do/will reset comp)

Next...The 99 don't like platinum or (E3) plugs...sorry...they work best with factory or Champion truck plug number 4412, They REALLY don't like platinum or split tip "cross-fire" plugs.

Next....check the firing order of the plug wires if you just changed them. I'll pull up a picture with the firing order in a minute and post it for you. A plug wire in the wrong spot = run like junk.

First I'd still get the codes pulled.
 
#11 ·
1st - just disconnected the gnd and did not touch it to pos. Battery, Plugs and Wires were changed a few weeks earlier when it was 1st happening (engine quits running traveling at speed limit)

Is PCM - Pulse Code Modulation or Powertrain Control Module

Here is a copy of info from a different post -

Ok Office 2010 won't let me make a picture out of it so here its long but it works I did it on my jeep 6 months ago after replacing the tps:

PCM Fast Learn Mode

The Jeep PCM performs several functions controlling Air Fuel ratios via Injector Bandwidth and Ignition Timing.

These outputs are controlled using the inputs received from all the sensors and then comparing these reading against a set of data tables burned into the PCM.

These memory tables are the brains that keep the engine running at low emissions and peak economy across the RPM band during closed loop mode.

These memory tables can and do change. They are adaptive, based on sensor readings, driving habits, engine performance and sensor tolerances.

Over time, the PCM Memory Tables become tuned to your engine.

This procedure first came to me from the folks at Avenger. I then verified it with a phone call to a Chrysler Engineer who had called me a year or so ago to ask about my experiences with a certain part on my TJ. I figured he owned me a favor. He had to check up on this for me. He called me back a week later and did indeed verify this procedure and what it does.

To the best of my knowledge it isn't documented in any of the FSM.


Forced Flash

This very simple procedure will Erase the Adaptive Memory stored inside the TJ PCM and allow a new Adaptive Memory to be developed.

After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.

Please perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.


Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
Reconnect the Battery Cable
Turn Ignition Switch to the On position but DO NOT start the engine
Turn Headlights On
Turn Headlights Off
Turn Ignition Key Off


The PCM Adaptive memory has now been flashed, or erased from the PCM.

When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory.

When you get the engine up to operating temperature the PCM will start to collect data for the Adaptive Memory.

The PCM will collect data for Adaptive Memory for the first 50 Warm-up Cycles.


Warm-up Cycle

A warm-up cycle happens when all of the following conditions exist.

Engine is running
A raise of 40F in engine temperature must occur ABOVE the engine temperature at start-up
Engine Coolant Temp must reach at least 160 F.


Once your engine has gone through 50 warm-up cycles in at least a 500-mile distance the PCM adaptive memory is set. It WILL NOT Change unless you flash it out and start all over again.
 
#13 ·
If you had the equipment that can go into the computer and see what the memory is doing, you'd know that the 30 second "touch the cables together" does NOT CLEAR THE MEMORY. It will clear the codes, but will not clear the complete memory.

There's only 2 ways to clear it -
One is to "force clear" it by sending a code into the computer, forcing it back to default - the basic information that it came from the factory with. That takes the DRB unit the dealer should have. Other scanners that claim they can are full of it!

The other way - leave the battery disconnected for at least 8 hours.

Try it - do the 30 second trick - no change? Then try the overnight trick.
Of course neither will correct the problem unless the problem is the PCM is using the data from a defective sensor.

It's not magic, just common sense.

Whoever made up the 30 second "touch" had no clue - just wishful thinking. It may discharge a few capacitors, but not the ones that count.
 
#15 ·
installed new crankshaft position sensor > engine idles rough, replaced with old crankshaft position sensor > engine idles smooth, checked camshaft position sensor in distributor, while cranking engine: output from 0-5 volts.
plugs, wires & battery replaced prior to changing CKP.:banghead:
Still get p1309, can reset, but returns. PCM > Pulse Code Modulation or Powertrain Control Module? Is the PCM in the engine compartment on firewall? What are the chances that the new crankshaft sensor is bad or does the engine have to warm up to get new signals over a period of time?
 
#18 ·
Not sure your problem was the same as mine but mine randonly shut off for no reason a few times and had trouble starting and staying running... Turned out tto be a dead battery , switched it out and goodbye problems... Dont know if thats it but ive seen stranger things happen so dont rule it out and its a simple thing to check
 
#19 ·
After replacing the Crankshaft position sensor with an aftermarket part. The sensor failed because it was missing a very important piece of the puzzle and no instruction/pictures.:bottom:
Bought new crankshaft position sensor from Chrysler Dealership...

Quote from Chrysler installation instructions:
"1. Be sure the paper/cardboard spacer has been installed to the bottom of the new sensor. If original sensor is being reinstalled (such as with transmission or flywheel removal), clean bottom of the sensor before installation. Obtain a new spacer and remove the paper backing. Install the self-adhesive side to bottom of sensor. This spacer MUST be installed. If spacer is not installed, sensor will be damaged when engine is started."

The aftermarket sensor did not come with a spacer and therefore it was damaged from the start!

After replacing with the sensor with spacer, it now runs good. Also had the dealership flash the settings and reset.:wavey:
 
#27 ·
I have been looking for this spacer too. The folks at the parts store had no idea what I was talking about.

I have a 98 TJ with the 4.0l, 5speed manual. Does anyone know if I need the paper spacer?
I'd like to know I have all the parts I need before I start taking apart my daily driver.
 
#31 ·
I stopped by the Chrysler service place on my way home tonight because the jeep stalled on me while in 6th gear. They look up my jeeps info by the VIN and showed me on paper that the paper spacer is required for my jeep. I got the spacer from them and drove him with zero issues. Hopefully it's fixed.

Jason
 
#35 ·
I'm dealing with a very similar issue. This has been very informative. Still sorting thru my no start issue. Pulling codes on Monday to see what shows up. Replace my coil and crank pos sensor so far with no results. See my thread for all the details and let me know what you think.

As far as this issue, how was it finally resolved? Was it one of the sensors that went bad, the coil, the brain or a combination of several things?
 
#36 ·
Did anyone ever find a solution for this issue?

I've replaced my camshaft and crankshaft sensors. The jeep runs when it starts and it will continue to run for a while before eventually the rpms jump and then it stalls out. It wouldn't be the fuel pump if the engine will run for about five minutes can it? Could the engine be siphoning enough fuel to stay running even without the pump?

It's an 06 unlimited wrangler, 4.0l
 
#38 ·
The engine can't siphon fuel so to answer your question, no it isn't the fuel pump. Your fuel injectors do not create pressure. They simply open and close allowing the existing pressure created by the fuel pump in the tank to pass through it so they do not have the ability to induce a vacuum to create the siphon effect.

When your jeep dies after 5 minutes or so will it start right back up or is it dead until everything cools back down. Sounds like you might have a sensor or something that is reacting to the engine temp and is going out after it gets hot.
mab, if the old CPS (crankshaft position sensor), wasn't bad why did you replace?
Also, a bad TPS (throttle position sensor) can produce these problems as well as a bad battery cable harness, or bad ground connection, or weak battery or...........Etc.
What I'm getting at is, that you need to check all of your electrical connections and wiring to eliminate a bad circuit somewhere.
Mab hasn't logged in since 2010 so I doubt he is going to answer your question. ;)
 
#37 ·
mab, if the old CPS (crankshaft position sensor), wasn't bad why did you replace?
Also, a bad TPS (throttle position sensor) can produce these problems as well as a bad battery cable harness, or bad ground connection, or weak battery or...........Etc.
What I'm getting at is, that you need to check all of your electrical connections and wiring to eliminate a bad circuit somewhere.
 
#39 ·
Thanks for the response coyote!

I'll give you some more detail..

Was driving in a topless day event when all of a sudden I get a flashing engine light and the jeep goes into limp mode (no rev past 3000).

When I parked it, it would crank and crank but not start, as if it was not getting fuel. I kept cranking it for about ten seconds at a time and eventually it started. Engine light only flashed on the first event, now it is just on. P0335 crankshaft position sensor circuit is the only code, as read from my super chips programmer. Side note, no tune is installed on the jeep I just had a tuner from my ram.

Installed a new ckp without a spacer. Cleared the code started the jeep, it started first crank and I rejoiced.. Less than a minute idling, it stuttered and shut off. Same code.

So I bought a new camshaft sensor and changed that. No change.

Then I read in this thread that m109 pilot had been told by the dealer that the 06 needs a spacer. I also have since read that the 06 6speed specifically needs a spacer, but when I called my dealer, they told me they don't see one.. I'm really hoping this is the culprit, and have ordered a new sensor and a spacer

I've checked the battery cables and cleaned the terminals. I've switched batteries with the one from my ram to confirm I didn't have a dead cell in my battery.

I have not done anything with the throttle body, but will try that next.


Currently the jeep sometimes starts and sometimes does not. I can put the pedal to the floor and crank it over and sometimes it catches. If I leave it idling when It does start, it runs for a while, then the rpms start to drop slowly until eventually she stalls out unless I rev her back up. Still the same lone code, 0335.


Thanks again for your response, I wasn't sure I could revive this thread!
 
#40 ·
Anytime. I would bet that it's the crankshaft position sensor that is causing your problems. I wouldn't mess with anything else until the new sensor and spacer are installed and you give that a try. Could you do me a favor? If you or someone you know has a set of digital calipers and could measure the thickness of the spacer and post that information up here that would be awesome. If you don't and you have a Harbor Freight or Sears near by you might take the spacer in and measure it in the store. You know... to test their tools out and see how accurate they are. ;)
 
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