Need your help DXing codes and readings

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Need your help DXing codes and readings

Postby jaxrodeo » Mon May 15, 2017 10:53 am

Hi guys. I’ve got a few intermittent warning lights on my 2004 Rodeo (Model R44, 2WD, 6 cyl, 3.2 liter, 65k miles) that I’d love your insight on. I spent 4-5 hrs reading threads w/similar issues, and trying several suggested tips. I’ve learned a lot, but haven’t found the problem yet. [NOTE: I’m a semi-novice, and I want learn as much as I can from you. I’m also broke due to medical bills and being out of work, so if I can DIY this it would be a lifesaver. I bought a multimeter last month and just picked up an OBD the other day. Still learning both.]

I. Chrono history (some may be unrelated but I figured it would be worth mentioning):
2004: Vehicle purchased (new).
2006: Cat. Converter replaced (recall).
2009: Starter replaced.
2011: Weird electrical issue begins. These issues still exist. (I don’t drive a lot at night.)
-Dash & stereo lights dim when brake pedal engaged.
-If headlights are on, both the cruise control and L+R brake lights don’t work (top does).
2011: ABS light starts coming on intermittently. (Sometimes stays on a few days then goes off for months.)
2015: Fuel pump replaced.
2016: Max setting (#4) of high speed blower stopped working. (Only speeds 1-3 work).
2017-4-9: CEL starts coming on intermittently (no noticeable issues).
2017-5-2: Reduced power light starts coming on intermittently (and vehicle loses power).
2017-5-12: Did first OBD2 scan. (Around 12pm; CEL is only light on at the time.) Found code definitions here.
Engine Codes:
P1125 (TP motor – fail safe mode)
P1295 (TP motor – power management mode)
P1515 (Throttle command/actual throttle position – signal variation)
P0507 (idle air control system RPM higher than expected)
P0563 (system voltage high)
Engine Freeze Frame:
DTCFRZF: P0563
FUELSYS1: CL
FUELSYS2: CL
LOAD_PCT: 16.5%
ETC: 176 F
SHRTFT1: 0.0%
LONGFT1: 8.6%
SHRTFT2: 0.0%
LONGFT1: 7.8%
MAP: 20.7 inHg
RPM: 1751/min
VSS: 48mph
Engine I/M Readings:
MIL status: ON
Misfire Mon: OK
FuelSysMon: OK
CompComp: OK
CatMon: OK
Htd Cat: N/A
EVAPSysMon: OK
Sec Air Sys: N/A
A/C Refr Mon: N/A
OxySensMon: OK
OxySensHtr: OK
EGR Sys: OK
2017-5-12: Used DVM and Vdc readings posted by Buster28 here to test (what I *think*) is the throttle body connector wires (circled in attached image). Colors / slots / results from two separate tests below:
Red/W (A) 4.55
Blue/W (B) .008-.01
Blue (C) 3.72
Red (D) 4.54
Green (E) .009-.01
Green (F) 11.92-12.08
Blue (G) 11.93-12.03
Green/W (H) .009-.01
2017-5-14: Did second OBD2 scan (cold start in morning; no lights were on at the moment)
Engine Codes:
P1125
P1295
Engine Freeze Frame:
DTCFRZF: P1125
FUELSYS1: OL
FUELSYS2: OL
LOAD_PCT: (not shown)
ETC: 102 F
SHRTFT1: 0.0%
LONGFT1: 0.0%
SHRTFT2: 0.0%
LONGFT1: 0.0%
MAP: 29.8 inHg
RPM: (not shown)
VSS: (not shown)
Engine I/M Readings:
MIL status: OFF
Misfire Mon: OK
FuelSysMon: OK
CompComp: OK
CatMon: INC
Htd Cat: N/A
EVAPSysMon: INC
Sec Air Sys: N/A
A/C Refr Mon: N/A
OxySensMon: INC
OxySensHtr: OK
EGR Sys: INC
A/T I/M Readings:
MIL status: OFF
Misfire Mon: N/A
FuelSysMon: N/A
CompComp: OK
CatMon: N/A
Htd Cat: N/A
EVAPSysMon: N/A
Sec Air Sys: N/A
A/C Refr Mon: N/A
OxySensMon: N/A
OxySensHtr: N/A
EGR Sys: N/A

II. Notes:
  • Since the RPL light started on 5/2, I’ve had 3 different situations occur whenever I start engine: 1) no warning lights; 2) CEL only; 3) CEL & RPL w/reduced power.
  • For example, on first start today in driveway: no lights. Next try (after taking DVM readings on TB): CEL only. 10 min later: CEL & RPL.
  • I’ve tried jostling wires in each situation, but haven’t noticed any changes in throttling.
  • I haven’t reset any codes.
  • I’m attaching a few misc pics of wires, just to show general condition.

III. Potential trouble spots (based on what I’ve learned in similar threads):
  • Wiring
  • Throttle position sensor
  • Throttle sensor on pedal
  • Throttle body
  • Alternator
  • Fuel tank pressure sensor

IV. My questions are:
  1. Do the codes and/or DVM results point to anything?
  2. Does the fact that almost every start results in a different combination of (or lack of) warning lights point more towards a wiring issue, even though jostling them hasn’t produced any changes?
  3. What would you suggest as a next step? Are there other sets of wires that I should test with the DVM?
  4. Is it normal for codes to go away on their own? (As shown in my 2nd test.)
  5. If I have to use the vehicle before this gets fixed, and I get stuck somewhere with the reduced power situation, will clearing that code be a temp fix — just so I can get home?

Apologies for the long post, and many thanks to anyone who can respond.

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Re: Need your help DXing codes and readings

Postby Buster28 » Mon May 15, 2017 1:35 pm

The attached schematics are for a 2004 3.2L engine, click on image to expand.
The schematic wire color codes for the throttle body connector match your posted info.

Did you make the voltage measurements with the 8 pin connector disconnected from the throttle body?
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Re: Need your help DXing codes and readings

Postby dant2002 » Mon May 15, 2017 1:55 pm

first thing for sure is clean your grounds going from alternator to frame and clean all your engine grounds and re tighten them. I have also pulled and cleaned the throttle position sensor before by carefully pulling it apart and gently cleaning the contacts. Also unplug and replug the alternator wires and make sure there hot wire is tight on the back. Grounds can cause many disturbances in voltages.

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Re: Need your help DXing codes and readings

Postby jaxrodeo » Mon May 15, 2017 3:32 pm

Buster28 wrote:The attached schematics are for a 2004 3.2L engine, click on image to expand.
The schematic wire color codes for the throttle body connector match your posted info.

Did you make the voltage measurements with the 8 pin connector disconnected from the throttle body?


Thanks Buster, I was hoping you'd reply.

Yes, I unplugged the 8-pin connector (circled in pink), put the key position to "ON", and then touched the positive end of the DVM to each of the 8 pin ports while touching the negative end to the negative battery post.

(Did you want me to do something with those two attached diagrams, or was that just an FYI?)
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Mon May 15, 2017 3:38 pm

dant2002 wrote:first thing for sure is clean your grounds going from alternator to frame and clean all your engine grounds and re tighten them. I have also pulled and cleaned the throttle position sensor before by carefully pulling it apart and gently cleaning the contacts. Also unplug and replug the alternator wires and make sure there hot wire is tight on the back. Grounds can cause many disturbances in voltages.


Can you point me towards what the "grounds" look like, and where they would be?

Also, what's the best way to clean them?

And just to confirm, is this the TPS:
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Re: Need your help DXing codes and readings

Postby Buster28 » Mon May 15, 2017 5:44 pm

DTC is P1515 is a Command - Actual Throttle Position Sensor (TPS) Correlation Error. The TPS is actually two separate TPS is a single package. The TPS is a variable resistor that is operated by the Throttle Valve. One TPS has a range of 0.5 to 4.95 Vdc and the other is 4.95 Vdc to 0.5 Vdc. As the the output voltage of one TPS increases in response to a movement of the Throttle Valve the output voltage of the other TPS decreases. The sum of the two outputs signals should equal the reference voltage.

In your measured voltage test the +5Vdc reference is +4.54 which is close to the expected but the voltage on Pin C (TPS1 output) is +3.72 Vdc as opposed to an expected voltage of close to 4.54 Vdc. It is possible this difference is causing the Correlation Error.
The PCM grounds (E-28. E-29, E30) are connected to the intake manifold bolts. Make sure they are clean and tight. Then rerun the voltage test making sure the battery is well charged.

The TPS assembly is the component in the purple rectangle your last posted image, but I don't think is the cause of your Electronic Throttle Control (ETC) problems.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Mon May 15, 2017 6:48 pm

Buster28 wrote:DTC is P1515 is a Command - Actual Throttle Position Sensor (TPS) Correlation Error. The TPS is actually two separate TPS is a single package. The TPS is a variable resistor that is operated by the Throttle Valve. One TPS has a range of 0.5 to 4.95 Vdc and the other is 4.95 Vdc to 0.5 Vdc. As the the output voltage of one TPS increases in response to a movement of the Throttle Valve the output voltage of the other TPS decreases. The sum of the two outputs signals should equal the reference voltage.

In your measured voltage test the +5Vdc reference is +4.54 which is close to the expected but the voltage on Pin C (TPS1 output) is +3.72 Vdc as opposed to an expected voltage of close to 4.54 Vdc. It is possible this difference is causing the Correlation Error.
The PCM grounds (E-28. E-29, E30) are connected to the intake manifold bolts. Make sure they are clean and tight. Then rerun the voltage test making sure the battery is well charged.

The TPS assembly is the component in the purple rectangle your last posted image, but I don't think is the cause of your Electronic Throttle Control (ETC) problems.



That's sooo helpful. Makes total sense. Two quick ones:
1.) Do I need to disable the battery before checking the PCM grounds, or is it safe to clean & tighten them while battery cables are connected?
2.) When you say "making sure the battery is well charged" -- do you mean run the vehicle for a bit, vs testing on a cold engine?
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Re: Need your help DXing codes and readings

Postby Buster28 » Mon May 15, 2017 8:24 pm

You don't need to remove be battery cables to check the PCM grounds but it is a good idea to make sure the battery cables are clean and tight as well.

A fully charged battery is about 12.6 Vdc. Since the PCM is using battery voltage during testing, low battery voltage could skew the results.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Tue May 16, 2017 9:12 am

Buster28 wrote:A fully charged battery is about 12.6 Vdc. Since the PCM is using battery voltage during testing, low battery voltage could skew the results.


Okay, I cleaned & tightened those three grounds... The battery (cold) is reading 12.7 Vdc, and with KeyOn it drops to 12.3. New throttle body readings:
Red/W (A) 4.5
Blue/W (B) .009
Blue (C) 3.69
Red (D) 4.5
Green (E) .010
Green (F) 12.05
Blue (G) 12.05
Green/W (H) .010

I assume this rules out a loose/dirty PCM ground? What's my next step?

Also, I just reran codes -- and now I'm seeing P1120 and P1220 (as well as the original 5). Should I clear any/all codes? (I'm not sure what that does.)
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Re: Need your help DXing codes and readings

Postby Buster28 » Tue May 16, 2017 10:30 am

Run the voltage test again except connect the meter negative lead to a PCM ground point on the engine.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Tue May 16, 2017 10:51 am

Buster28 wrote:Run the voltage test again except connect the meter negative lead to a PCM ground point on the engine.


Throttle body readings w/meter negative lead connected to PCM ground point:
Red/W (A) 4.4
Blue/W (B) .005
Blue (C) 3.60
Red (D) 4.38
Green (E) .005
Green (F) 12.04
Blue (G) 12.04
Green/W (H) .005

FWIW, after the readings I started the engine but accidentally forget to reconnect the throttle body connector, and it started in reduced power mode. Once I realized this, I turned it off, reconnected, and it restarted fine (*not* in reduced power mode), although the CEL was on.
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Re: Need your help DXing codes and readings

Postby Buster28 » Tue May 16, 2017 12:47 pm

With every thing connected up clear the codes and start the engine, if the CEL illuminates shut the engine off and see what codes are set. If the CEL does not illuminates drive slowly in 1st gear until the CEL illuminates, shut the engine off and read the codes.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Tue May 16, 2017 1:53 pm

Buster28 wrote:With every thing connected up clear the codes and start the engine, if the CEL illuminates shut the engine off and see what codes are set. If the CEL does not illuminates drive slowly in 1st gear until the CEL illuminates, shut the engine off and read the codes.


Cleared codes, started engine, no CEL, drove about 3 miles in low gear (10-20mph) but no CEL. Ran codes again; says "0" found but shows the high voltage code when I select "engine" (P0563).
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Re: Need your help DXing codes and readings

Postby Buster28 » Tue May 16, 2017 4:39 pm

DTC P0563 indicates the alternator voltage is above 16 Vdc . That will cause the PCM to be erratic and would affect the Electronic Throttle Control system. Monitor the voltage across the battery terminals while increasing RPM.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Wed May 17, 2017 7:43 pm

Buster28 wrote:DTC P0563 indicates the alternator voltage is above 16 Vdc . That will cause the PCM to be erratic and would affect the Electronic Throttle Control system. Monitor the voltage across the battery terminals while increasing RPM.


Well, I drove it about 50 miles (with approx 15 different ignition starts) since the last step that we did yesterday, and it was code-free -- until about an hour ago when the CEL came back on. (But it hasn't been code-free for that long in about a month.)

Now it's showing 3 codes:
1) P0563
2) P0116 ("Engine Coolant Temperature Sensor 1 Circuit Range / Performance")
3) P0563 (but this one has a little "pd" symbol next to it; maybe it means "pending"?)

The battery reads 12.54 cold, and then when I started it and gave it RPMs I got it up as high as 14.21. (But nowhere near 16.) And that's with the most recent CEL on. Any ideas?

And here's the freeze frame data for P0563, in case that's pertinent:
DTCFRZF: P0563
FUELSYS1: CL
FUELSYS2: CL
LOAD_PCT: 27.1%
ETC: 127 F
SHRTFT1: 1.6%
LONGFT1: 8.6%
SHRTFT2: 0.8%
LONGFT1: 10.2%
MAP: 21.6 inHg
RPM: 2332/min
VSS: 13mph
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Re: Need your help DXing codes and readings

Postby Buster28 » Wed May 17, 2017 7:49 pm

The expected Engine Coolant Temp (ECT) is around 180F and your Freeze Frame chart shows 127F. How long had the engine been running?
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Wed May 17, 2017 7:58 pm

Buster28 wrote:The expected Engine Coolant Temp (ECT) is around 180F and your Freeze Frame chart shows 127F. How long had the engine been running?


The CEL came on about 30 seconds after starting the car. I couldn't run the codes right away, but when I did, the engine had been running for about 20 minutes.
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Re: Need your help DXing codes and readings

Postby Buster28 » Thu May 18, 2017 4:23 am

You listed DTC P0116 as a current fault but that is not a valid number so you may or may not have an Engine Coolant Temp (ECT) problem. Monitor the ETC sensor output using the live data mode on your scan tool. Interestingly the Electronic Throttle Control System faults have not returned.
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Re: Need your help DXing codes and readings

Postby jaxrodeo » Fri May 19, 2017 8:14 am

Buster28 wrote:You listed DTC P0116 as a current fault but that is not a valid number so you may or may not have an Engine Coolant Temp (ECT) problem. Monitor the ETC sensor output using the live data mode on your scan tool. Interestingly the Electronic Throttle Control System faults have not returned.


1) re: P0116... I don't think my OBD has a live data mode. (This is the model I have.) Would it be any use if I drove around with it plugged in so I can run the codes & freeze frame data as soon as the CEL comes on?

2) re: P0116... Coolant question: The radiator appears full, but the side reservoir is empty. The cap says "coolant only", so I was going to fill it -- but then I read that you're only supposed to add coolant via the radiator, not directly to the reservoir. Any truth to that? And should I fill the reservoir?

3) re: P0563... Are there any alternator tests that you recommend I run with the multimeter?

4) re: throttle control codes... Perhaps cleaning and tightening those grounds fixed it? (Because the reduced power warning hasn't kicked in since then.)

Thanks again.
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Re: Need your help DXing codes and readings

Postby Buster28 » Fri May 19, 2017 11:21 am

You have a code reader as opposed to a scan tool, since DTC P0116 is not a valid code for your truck the reader probably needs to tossed out in favor of a real tool like an Innova 3160.

The coolant bottle should have some coolant in it but with room for expansion of hot coolant from the radiator when necessary.
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