😁Hey gang, new here, thanks for having me.

I have an 08 xD RS1.0. I purchased recently and noted that from Day 1 it idles lower rpms and rough when shifting from Park or Neutral into Reverse or Drive. This problem increased in the short amount of time I've had it.

The car when at idle doesn't seem to like the current load from the radiator fan coming on, the A/C, the blower. When these are on the idles becomes lower and rougher and the car is on the verge of shutting off.

I took the car to have oil changed and tranny flushed (and that very day a CEL came on minutes prior to the service shop, it was the MAF sensor, after cleaning with MAF code was no more) and the servicemen accidentally spilled transmission fluid and hosed the engine block while car was off to clean. Obviously not ideal. Following service I drove to the gym for my workout, when finished roughly 90 minutes later the car didn't start. This was a first, I checked battery terminals and they felt loose. After pushing down on them further and starting car, no issue. Drove home, parked car. The next day, difficultly starting. I found that when I put my foot to the floor on the accelerator it would eventually start. (I can hear intake sucking during start and can smell gas, thus spark being the remaining question during start up) I tested battery, it needed replaced, did so as well as new terminals. Checked all fuses=good, checked grounds=good. I replaced intake and filter. Problem persisted. MAF used to clean MAF sensor as mentioned prior. Crc to clean the throttle body. Problem persisted. Lucasoil in the fuel to help clean injectors. Problem persisted. Seafoam. Problem persisted. Sprayed starter fluid around intake to check vacuum leaks. Problem persisted.

It takes multiple times of attempted starts to fire up. No rhyme or reason. Once going it is smooth, no hesitation. When I come to a stop it acts like it's going to die. Spark plugs and coil packs are en route. I have never encountered this issue and have had 6 people whom are very knowledgeable look at it and ask what I had done and when I mention what has been done they all scratch their heads. We have all read on the internet of somewhat similar issues but rarely has there been a clear idea as to the cause and how to fix. Mechanics in my area are backed up for months with the pandemic. Although long winded I have done my best to relay this saga over the last couple of weeks, thanks for reading...

I would greatly appreciate your help guys. 😁


*Moved to Correct Forum by Administrator

Sticky Where to Post Your Question

Sticky How To Advanced Search SL (Scion Life)

______________________________

 

I've fixed this in less than 5-minutes multiple times at my shop. There can be many different causes, so we'll need to gather some hard quantitative objective data. This is critically important for diagnostics that different people agree on same thing (especially in different locations).

For example, many people will agree that sun came up at 6:16am today for most of U.S. Or that when measuring your tyres, 0-psi is problem. Much easier to understand and agree on facts than "it seems low", or "felt kinda hard". So keep that in mind when reporting data to help us diagnose your issues. What matters most is numbers, which we will compare to standards in manual.

Here's how we're gonna gather some hard data, get one of these:
https://www.harborfreight.com/7-func...ter-63759.html

Learn how to use it to measure voltage and resistance (for now).
https://learn.sparkfun.com/tutorials...multimeter/all

Get service manual and figure out where various sensors are: TPS, MAF, IAT, ECT, O2 (upper). Go over manual's guide on how to test these sensors. Then we're gonna measure them.

1. with engine OFF, measure resistance between TPS's idle-switch contacts. ohms = ???

2. with cold engine, start up and immediately measure following:
a. MAF output voltage = ???
​​​​ b. TPS output voltage = ???
c. resistance of IAT, ohms = ???
d. resistance of ECT, ohms = ???

3. after engine warms up, re-do all measurements a-d above. Post 9 measurements you've taken.

Competent mechanics have been using multimeter to diagnose issues for over 100-yrs. Tried and true techniques to home in on problems quickly without running in circles. No wasting time swapping perfectly-working parts with brand-new perfectly working parts and nothing changes. Other most helpful tool is vacuum-gauge. We'll get to that next depending upon results you measure...

 

Thank you for your reply I greatly appreciate it... Since my last post the xD hasn't been drivable it will hardly ever start and idles so rough it dies quickly.. I haven't been able to accomplish all of the things you have asked but I do have hard data on what I was able to test... multimeter stats first then computer stats

Multimeter
-Throttle position sensor
Yellow. 93
Green .23
Red .23

Yellow 4.96
White 5.06
Pink 4.96
Black 0
Green .24
Red .24

-MAF
Black 12.19
MAF test 12.53-12.54 Flucuated
vg e2g 5.05

MAF ohm .58 with harness on and key on car off

I ran out of time today to directly Test IAT or ECT but have computer results that list numbers for them.

I ran diagnostic in computer 1) off position, 2) when I had it running today briefly, 3) after I swapped MAF sensor to see any difference. Here are the results
1)
-Shrtft1 -0
-Longft1 -3.1
-Iat 33 degrees
-Maf 0.14g/s
-TP 15.7%
-02SLOC B2S4/B2S3
-02B1S2 0V
-SHRTFTB1S2 99.2%
-RUNTM 0sec
-MIL 0Km
-EQ RATB1S1 Flucuated between 1 and .999
-02B1S1 Flucuated between 3.300 and 3.301
-EVAP PCT 0
Warms ups 0
-CLR DIST 0
-BARO 98kPa
-EQ RAT11 Flucuated between 1 and .999
-02B1S1 0 mA
-CATEMP11 463.3 degees C
-CATEMP12 282.3 degrees C
-VPWR Flucuated between 12.011 and 11.992
-LOAD_ABS 0.0%
-EQ RAT 0.473
-TP_R 0
-ATP_B 47.1
-ATP_D 15.7
-ATP_E 31.8
-TAC_PCT 15.7
-MIL TIME O
-CLR TIME 17
-EVAP VPA Flucuated between 98.930 and 98.905 kPA

2) Here is after I had it running

-Load-PCT 31%
-ECT 77 degrees C
-Shrtft1 2.3
-Longft1 3.1
-Spark Adv 10.5
-Iat 26 degrees C
-Maf 3.32g/s
-TP 15.3%
-02SLOC B2S4/B2S3
-02B1S2 .135V
-SHRTFTB1S2 99.2%
-RUNTM 491sec
-MIL DIST 0Km
-EQ RATB1S1 .993
-02B1S1 Flucuated between 3.222v
-EVAP PCT 33.3
-Warms ups 1
-CLR DIST 0
-BARO 98kPa
-EQ RAT11 Flucuated between .970
-02B1S1 - 0.094mA
-CATEMP11 516.4 degees C
-CATEMP12 353 degrees C
-VPWR 13.710
-LOAD_ABS 20.0%
-EQ RAT 1
-TP_R 0
-ATP_B 46.7
-ATP_D 15.7
-ATP_E 31.8
-TAC_PCT 15.3
-MIL TIME 8 min
-CLR TIME 37
-EVAP VPA 98.905 kPA

3) After I swapped in a new MAF sensor (to see what difference it made) and got it started again

-Load 40%
-ECT 91 degrees C
-Shrtft1 -2.4
-Longft1 3.9
-Iat 33 degrees C
​​​​​​-SPARKADV 14 degrees C
-Maf 22.12g/s
-TP 29%
-02SLOC B2S4/B2S3
-02B1S2 0.740 V
-SHRTFTB1S2 99.2%
-RUNTM 580sec
-MIL 8Km
-EQ RATB1S1 Flucuated between 0.994
-02B1S1 Flucuated between 3.151V
-EVAP PCT 42%
-Warms ups 1
-CLR DIST 8
-BARO 99kPa
-EQ RAT11 Flucuated between 1.017
-02B1S1 -0.008 mA
-CATEMP11 739.2 degees C
-CATEMP12 658.6 degrees C
-VPWR Flucuated between 13.750
-LOAD_ABS 60.4%
-EQ RAT 1.000
-TP_R 14.9%
-ATP_B 66.3%
-ATP_D 29%
-ATP_E 41.2%
-TAC_PCT 24.7
-MIL TIME 10 min
-CLR TIME 61 min
-EVAP VPA Flucuated between 98.455 kPA

 

Any ideas? Still have the same issue, any help would be appreciated, thanks

 

Hi, welcome back!

We still don't know if your TPS's idle-switch is making contact when throttle is let up. This signals to ECU that pedal is let up all way. ECU then adjusts throttle-position to manage engine speed. It's like you holding throttle open slightly to keep engine speed steady. ECU will ONLY manage idle speed when it detects closed throttle. IF idle-switch doesn't close and make contact, ECU won't adjust to maintain steady idle-speed.

So here are critical tests again. Takes 5-min or less to fix this once we have proper data from tests:

1. with engine OFF, measure resistance between TPS's idle-switch contacts. ohms = ???

2. intake-manifold vacuum with warmed-up engine. Vacuum =???

There is nothing wrong with your car. As in a broken part that you can just replace and it'll work perfectly. This is an adjustment issue, where a screw or a part needs to be rotated 5-degrees one way or the other to fix. The numbers you measure will determine which way to turn screws and by how much.

Also are there any diagnostic codes reported by ECU?

 

I cannot get these numbers as stated previously as the car still will not start, even with trickle charges or jumper pack. It acts like it will fire right up, it turns over but nothing. There is a CEL and a Battery Light. The battery has been replaced brand new with brand new terminals, was thinking perhaps alternator or fuel pump as when gas pedal is pumped it acts even more as though it's going to start. In the past this would at times help. With it being 14 years old and them not being replaced do you think it can hurt? Also replaced plugs and coils again as another measure. I have checked all fuses and relays, with meter also. Starter fluid in intake didn't help to get it started either. Unsure what could've changed adjustment wise for it start idling rough and die at stop signs, during that time battery light would come on making me think alternator as this happened in an Accord I had and was the fix. Any other ideas or tests until it gets started? You mention the TPS? Can you tell me how to test that on the xd I was under the impression we do not have a TPS on Xds, that is why perhaps I didnt get the correct numbers before? Maybe a youtbe link or something? I am not the most mechanically onclined but trying my best. Im never afraid to admit when I am wrong, I want to learn what is wrong and hopefully be able to help others. I have seen probably 500+ posts from other scion owners in similar boats with out a fix. It's weird I have had 4 different computers hooked up, no codes, 2 of the computers were $3000+ ODB.
Really need the help I am a vet on a fixed income. Thanks for your reply.

 

How did you get those scanner readings before & after replacing MAF if car's not running? Codes can be read by scanner with engine not running.

Again, there is nothing broken with your car! DO NOT randomly replace parts until you've tested them by measuring and comparing those numbers with standards in manual. If numbers don't match, then yes, it may be a bad part. Replacing perfectly-working parts with brand-new perfectly-working parts changes nothing and problems will persist.

For example, go ahead and replace all headlight and tail-light bulbs. Also all dash and interior bulbs.

Battery-light when running is actually known as "charge lamp" and indicates that battery is not charging. This is usually problem with alternator. Replacing perfectly good battery with brand-new perfectly good battery will change nothing because alternator is still bad. Let's back up and test battery to determine if it's good or bad before replacing:

3. measure battery voltage with everything OFF. Voltage = ???

4. measure battery voltage during cranking. Voltage = ???


Same thing with TPS, it's NOT BROKEN! Just needs to be adjusted so idle-switch is connected when you let off throttle. Even if you were to replace perfectly-working TPS with brand-new perfectly-working one, you will still have to measure and rotate it to correct angle for idle-switch to be closed. Lemme see if there's a page or 2 from manual I can find on TPS adjustment.

There's also very likely vacuum leak that may be causing problem. This allows engine to suck in air that won't flow past MAF-sensor and get measured by it. MAF will report less-than-actual air-flow and ECU will inject lower-than-required amount of fuel. Thus will be less fuel than needed for actual flow into engine. Vacuum-leak is NOT from vacuum-hoses, but from leaking intake plumbing. Inspect all plastic & rubber pipes and ducts and clamps leading to throttle-body. Especially on underside where you can't see it (use mirror on a stick). Hose that attaches to throttle-body loves to slip off underneath clamp. Everything should firmly attached and sealed.

Of course, ultimate test for vacuum-leak is measuring intake-manifold vacuum when engine's running. If it won't even start due to massive vacuum-lrak, then we can't measure that. But we can measure a proxy.

5. measure MAF output voltage where it goes into ECU during cranking. volts = ???

This will at least give us an idea if it's reporting proper amount of air-flow. If less-than-normal, then we know air is sneaking in other than through MAF and we should look closer for leaks.

 

There are actually TWO TPS in car. One down by your foot and one on throttle-butterfly. They need to be rotated and adjusted so their output signals are in sync, otherwise ECU will get confused and go into failsafe mode. Which makes car barely drivable.

Combined with vacuum leaks and it's not surprising it won't start. Again, NOTHING is broken and needs replacing. This is purely an adjustment procedure. It's like wall-clock that's hung up at an angle. It's still working, but depending upon how you look at it, may be getting wrong time.

Don't need scanner, voltmeter has served mechanics for over 100-yrs.

https://www.700r4transmissionhq.com/p0121-scion-xd/

 

The other battery was dead and original that couldn't be revived unfortunately via charging, do not recall reading but much below 12, so I replaced it.

With car off I can hook up computer and do a quick read and screen shot photos so you can see what I see.

No Codes at all but can give other diagnostic readings.

When I Google TPS 2008 scion xd I cannot find any information on it? What it looks like? Location? How to fix? From what I read many say it doesn't have one, please prove me wrong so I can see about fixing this and help others find and fix lol

You mention adjusting the throttle such as turns.
How do I do that if I don't have TPS? Is there another way? Do I hook up the meter somewhere (point me where please) and then by hand open the butterfly valve or press the accelerator pedal? With computer hooked up?

I was able to google Accelerator Pedal Position Sensor for the 2008 xd, is this the sensor by my feet you're referring to? If so how would this be tested? The video you linked was great I understand what he did, but do not know how to apply that to my situation with the interior pedal sensor? If you help me get this I'd be happy to paypal you for your time and consideration 😊

 

Starting volts from attempting to start the other day was 10.23v. After not starting disconnected negative cable.
So dropped from 10.23- 9.72 with just plugging computer in to read parameters. I will leave both cables connected as lately when connected the battery voltage will go up on its own with car off... never seen this before? Does this seem normal? I will record number at the end of this message with time elapsed and new voltage from battery.

TP only going to 81.2 When gas pedal is to the floor. Noticed tp, tp r, atp b, atp d, atp e, tac pct, all change look at before after. Evap vpa was going between 98.510-535-55 nonstop without gas pedal. When gas is pressed maf goes from .15g/s to .14g/s.

After minutes the cars voltage has went up to 10.16 Volts from 9.72v.




First reading with key switched to on not started(because it won't start) long enough to take obd computer reading



Roughly 20 minutes later with car off it has recharged a fair amount, is this normal?

 

 

I am really trying my best here, hope this helps. Do you see anything out of the ordinary???

 

Readings look OK for not running. SHRTFTB1S2 99.2% seems off, maybe it'll correct once running. Battery should be on trickle charger. Such low voltage is barely enough to crank engine over and too low to properly power ECU.

No PayPal necessary, least I can do for your military service, thank you!

You can download manuals from here. Has all testing and adjustment procedures needed.
https://www.scionlife.com/forums/sci...manual-188666/

 

I appreciate you sharing the link. I had previously downloaded those last year prior to posting about issue. I skimmed through them and skimmed through the forum to find ideas on how to fix this.

I skimmed again yesterday after your reply and cannot find the fixes you were speaking of? So from here what can I do? I don't have the income to take it to a shop, and have always tried my best to learn how to fix something if I can find the problem or am in the know of how to fix it lol YouTube University if you will.

The Xds are great cars but there is not much information out there on all these non starting issues with no codes but CEL on. It's so frustrating lol
After looking at those numbers what should I do now? Can you tell me steps to take in what order, please 🙏
When looking through wiring I also cannot find the ground strap for the engine, can you point me in the right direction?

Also I'll trickle her again, currently quite a downpour here.

I appreciate your words and thanking me for my service. I love this county and my fellow brother and sister 😊

 

i'll to through manual this weekend and find relevant testing sections for you.

 

Got it started and it ran for 20 minutes or so before it idled down. alternator couldn't keep up, got video while it was running of alternator voltage dropping and then dying.

I managed to pull diagnostic numbers while running. Here they are-

 

Any ideas Danno? You'd mentioned looking in the manual over last weekend to get some ideas?

Also worth noting I got started again earlier today, was able to drive it around and ran computer and came up with pending code= 0304 cylinder 4 misfire, which is odd as plugs and coil packs were just replaced 2 weeks ago. Going to try and swap 3 and 4 and see what happens.

Lastly after it running for nearly 90 minutes, 45 of that driving I had no issues until I pulled in the driveway and shifted into reverse at which point car idles down low at this point I check voltage and it went to 12 and then died, battery was then at 10 and obviously would not start. Trickle charging again. The care ran beautifully, no issue at all lol
Danno whatcha thinkin 🤔?????
P.s. also have pictures of all the numbers while driving if you want to see???

 

First, I don't like scanner data because it's interpreted from real measurements of sensor voltage, resistance, etc. Would like to get some real hands-on data like actual intake-manifold vacuum numbers and MAF output voltage. Can you change settings on scanner to show MAF voltage?

Also car doesn't use MAP sensor, so where is it getting data for BARO? This makes all other data suspect.

As for misfire, as I mentioned earlier, don't replace parts until you've tested them and measurements confirm they are bad. Many auto-parts from stores are bad right out of box. So now, you've got 8 coils to test and measure instead of just 4. Measure all coils:

ORIGINAL COILS

1. #1 coil primary impedance = ???
2. #1 coil secondary impedance = ???
3. #2 coil primary impedance = ???
4. #2 coil secondary impedance = ???
5. #3 coil primary impedance = ???
6. #3 coil secondary impedance = ???
7. #4 coil primary impedance = ???
8. #4 coil secondary impedance = ???

REPLACEMENT COILS

1. #1 coil primary impedance = ???
2. #1 coil secondary impedance = ???
3. #2 coil primary impedance = ???
4. #2 coil secondary impedance = ???
5. #3 coil primary impedance = ???
6. #3 coil secondary impedance = ???
7. #4 coil primary impedance = ???
8. #4 coil secondary impedance = ???

From this list, we should be able to at least pick out 4 good coils and toss out 1 or 2 that's bad.


Does appear alternator is not charging battery. How does battery-cable terminals look? Keep on charger for 24hrs, then disconnect. Do these measurements:

1. Battery voltage with everything off
2. Battery voltage during cranking
3. Battery voltage with engine at idle
4. Battery voltage with engine at 2500rpm

Numbers point out suspect components and tell us where to look next.

 

I replaced the coils a year ago and with its behavior I swapped them for new ones free of charge is it seemed they were the issue. May have helped as it has started twoce since doing so vs not at all prior.






They were not tested as I didn't know how. After you comments to test I'll do so when the weather shapes up, its raining hard here.

Ill post more of the newest pictures of my current drive and computer numbers.