Check engine light

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
It is an internal failure in the pcm. It has to be replaced. You need a new, not used, computer, flashed and you will be back on the road.

Roy
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
DAKOTABOY2002
  • MEMBER
  • 19 POSTS
Ok so I just picked up my truck from the transmission shop and no bs a block down the road the check engine light came back on so I stoppped and got the P0748 error code again, they replaced the solenoid valve twice now and checked all the wiring harnesses this would be the 4th time taking it back there for this error code
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
DTC P0748: GOVERNOR PRESSURE SOL

Circuit Description
Circuit is monitored continuously while ignition is on. DTC sets if voltage detected on governor pressure solenoid control circuit at the PCM does not match desired voltage.
Possible Cause
The following items may be area of concern:
Fused B+ circuit open.
Solenoid and harness assembly defective.
Governor pressure solenoid out of tolerance.
***********************************
Transmission control relay defective.
Governor pressure solenoid control circuit shorted to ground.
Governor pressure solenoid harness defective.
Governor pressure solenoid control circuit open.
Transmission control relay output circuit open.
Transmission control relay output circuit shorted to ground.
DTC P1765 is set.
PCM defective.
Diagnostic Procedure
Using scan tool, read DTCs. If good trip counter for DTC P0748 is not displayed or displayed count is not zero, go to step 16. If good trip counter is displayed and displayed count is zero, go to next step.
Using scan tool, read DTCs. If DTC P1765 is also set, see DTC P1765: TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT. If DTC P1765 is not set, go to next step.
Using scan tool, read transmission DTCs. If DTC P0743, P0748 and P0753 are present, go to next step. If DTC P0743, P0748 and P0753 are not present, go to step 8.
NOTE:When testing fused B+ or output circuit with a test light, ensure test light illuminates brightly. Compare test light brightness of circuit to brightness of test light when connected to direct battery voltage. If circuit does not illuminate with same brightness as direct battery voltage, circuit must be repaired.

Turn ignition off. Disconnect transmission solenoid harness connector. Inspect connector and terminals for damage. Repair as necessary. Turn ignition on. Using test light connected to ground, check fused transmission control relay output circuit at transmission solenoid connector terminal No. 1. If test light illuminates brightly, replace transmission solenoid assembly (internal transmission harness). See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS. If test light does not illuminate, or does not illuminate brightly, go to next step.
Turn ignition off. Remove transmission control relay from underhood Power Distribution Center (PDC) or Integrated Power Module (IPM), as applicable. Turn ignition on. Using test light connected to ground, check fused B+ circuit at transmission control relay connector terminal No. 30 (terminal C3 on AB body). If test light illuminates brightly, remove test light and go to next step. If test light does not illuminate, or does not illuminate brightly, repair circuit for open. If fuse is open, ensure to check for short to ground or high resistance in fused B+ circuit.
Turn ignition off. Measure resistance between ground and fused transmission control relay output circuit at transmission solenoid connector terminal No. 1. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair relay output circuit for short to ground.
NOTE:When testing output circuit with a test light, ensure test light illuminates brightly. Compare test light brightness of circuit to brightness of test light when connected to direct battery voltage. If circuit does not illuminate with same brightness as direct battery voltage, circuit must be repaired.

Using fused jumper wire, jumper fused B+ circuit (terminal No. 30 (terminal C3 on AB body) and transmission control relay output circuit (terminal No. 87 (terminal C5 on AB body) together at transmission control relay connector. See WIRING DIAGRAMS. Turn ignition on. Using test light connected to ground, check fused transmission control relay output circuit at transmission solenoid connector terminal No. 1. If test light illuminates brightly, replace transmission control relay. If test light does not illuminate, or does not illuminate brightly, repair relay output circuit for open. If fuse is open, ensure to check for short to ground or high resistance in relay output circuit.
Turn ignition off. Disconnect PCM harness connector C2 (White) and transmission solenoid harness connector. Measure resistance of governor pressure solenoid control circuit between PCM harness connector C2 (White) terminal No. 8 and transmission solenoid harness connector terminal No. 5. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair governor pressure solenoid control circuit for open.
Measure resistance between ground and governor pressure control circuit at PCM harness connector C2 (White) terminal No. 8. If resistance is less than 5 ohms, repair governor pressure solenoid control circuit for short to ground. If resistance is 5 ohms or more, go to next step.
Turn ignition on. Measure voltage of governor pressure solenoid control circuit. If voltage is more than.5 volt, repair governor pressure solenoid control circuit short to voltage. If voltage is.5 volt or less, go to next step.
Turn ignition off. Remove transmission control relay from underhood Power Distribution Center (PDC) or Integrated Power Module (IPM), as applicable. Measure resistance between governor pressure solenoid control circuit and all other circuits at transmission solenoid connector. If resistance is less than 100 k/ohms between governor pressure solenoid control circuit and any other circuit, repair circuit as necessary. If resistance is 100 k/ohms or more, go to next step.
Measure resistance of governor pressure solenoid control circuit between fused transmission control relay output circuit at transmission solenoid connector terminal No. 1 and PCM harness connector C2 (White) terminal No. 8. If resistance is 3-6 ohms, go to next step. If resistance is not 3-6 ohms, replace transmission solenoid assembly (internal transmission harness). See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS.
Measure resistance between ground and governor pressure solenoid control circuit at transmission solenoid connector terminal No. 5. If resistance is less than 5 ohms, repair short to ground in transmission solenoid assembly. If resistance is 5 ohms or more, go to next step.
Measure resistance between TCC solenoid control circuit and governor pressure solenoid control circuit at PCM harness connector C2 (White) terminals No. 8 and 11. Resistance should be 28-68 ohms. Measure resistance between governor pressure solenoid control circuit and 3-4 shift solenoid control circuit at PCM harness connector C2 (White) terminals No. 8 and 21. Resistance should be 28-68 ohms. If resistance for both measurements is within specification, go to next step. If resistance is not as specified, replace transmission solenoid assembly (internal transmission harness). See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS.
Measure resistance between governor pressure solenoid control circuit and all other transmission solenoid assembly circuits at appropriate PCM harness connector terminals. If resistance is less than 100 k/ohms between governor pressure solenoid control circuit and any other circuit, replace transmission solenoid assembly (internal transmission harness). See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS. If resistance is 100 k/ohms or more, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE.
Conditions required to set DTC are not currently present. Inspect all applicable connectors and terminals for damage. Repair as necessary. If connectors and terminals are okay
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
MUSTANGXXX
  • MEMBER
  • 27 POSTS
  • 2002 DODGE DAKOTA
  • 980,000 MILES
Check engine light keeps coming on, then after a while it goes off, but always comes back error code is po601 pcm internal fault do I have to replace the pcm or is there a way of checking the pcm
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
ECU or PCM can be tested, check with your mechanic on who can do this in your location, it is a specialist job, your mechanic should have a contact for this sort of work.
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
IOWA_MALE
  • MEMBER
  • 1 POST
  • 2002 DODGE DAKOTA
  • V8
  • 2WD
  • AUTOMATIC
  • 108,000 MILES
Code is p0121 can u tell what it is and how much to fix it
thank you
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS


https://www.2carpros.com/forum/automotive_pictures/62217_dakota_1.jpg


Not sure how much, but it's the sensor on the gas pedal...look up price here:
https://www.2carpros.com/kpages/auto-parts-store.htm
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
BOOMER02
  • MEMBER
  • 3 POSTS
  • 2002 DODGE DAKOTA
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 85,000 MILES
My service engine light is on, what causes this?
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
If the light has come on, there could be many things that caused it. However, to determine the problem, you need to have the computer scanned. IT will identify where the problem came from. WHat to do is take the truck to a nationally recognized parts store and have them do it. Most will do it for free. Once they get the trouble code, let me know what it is and I can direct you.

Joe
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
BOOMER02
  • MEMBER
  • 3 POSTS
The code says we have a vacume leak. We tried to tighten the gas cap, but still have light on. Where should I check now?
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Okay, it sounds like you have a leak in the "EVAP" system. First, it isn't very often that there is a problem with the fuel cap. Parts stores will sell them any time there is a leak. Let me know if they told you there was a leak in the EVAP system so I know how to direct you. Don't worry, we'll figure this out.

Joe
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
BOOMER02
  • MEMBER
  • 3 POSTS
Yes that is what he said
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
AO7777
  • MEMBER
  • 17 POSTS
  • 2002 DODGE DAKOTA
  • 170,000 MILES
I have don't nothing yet just used my obdII scanner to get the code. Can it be spark plug, rotor and cap? I don't have compress gage and other compress gages.
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Here is what I recommend. Because the leaks can come from so many different places, they are hard to find. Contact your local shop and tell them you need to have the EVAP system fogged. What they will do is actually pump fog into the system at a low pressure. When it hits the leak, it will leak from the system and you can identify the problem. Otherwise, you will be looking for the problem and never find it. You can try to save time and money and have the fuel cap checked first. However, chances are it is fine.

Let me know what you find.
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Start with a compression test. It sould be that, plug, coil, vacuum leak or injector. This is why you need a real diag before throwing parts at it.

Roy
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
AO7777
  • MEMBER
  • 17 POSTS
Do I need a compression Tester and which cyn hole? #3? How do I do a compression test?
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Remove the plug. Unplug all coils. Crank engine with tester installed and read the readings for us

Roy
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
DAKOTABOY2002
  • MEMBER
  • 19 POSTS
  • 2002 DODGE DAKOTA
  • 90,000 MILES
Hello, my question is my Dakota is making this loud sound when accelearting had a friend with me sounds like its coming from the Drivers side of the car, its like a burst of air only really happens when going above 2 RPM's, does not happen while idling or at startup, could this be the cat converter? I checked the muffler doesn't seem like there is a hole in it, ive heard about cat converters getting clogged, also NO check engine lights are on as of now, but the acceleration is really slow, let me know if you need anymore information thanks guys
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Sounds like you are on the right track. You can verify it by checking the back pressure

Roy
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)
Tiny
DAKOTABOY2002
  • MEMBER
  • 19 POSTS
How do I check the back pressure?
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Tuesday, July 14th, 2020 AT 11:52 AM (Merged)

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