Error code 42 transmission

[HejsanKwaheri]

I am trying to finish up a rebuild on a 1993 80 series. I have no cruise or speedometer, it runs in limp mode and doesn’t want to upshift. I run the code and it shows only 42. The vss is new and reads correctly. I disassembled the wiring harness from the vss and no issues there. I inspected the entire wire harness during the rebuild and changed pigtails when needed and rewrapped. Next idea is the instrument display. Wanted to get feedback before I tackled that task. Thank you.

 

[Malleus]

To be clear about the operation of the A442F transmission: there is no "limp mode". The transmission either works or it doesn't. The TCM (transmission control computer) has no special programming for limiting the operation under any conditions. This is true for every 80 series Land Cruiser. "Limp mode" is a safety feature built into late model computers which operate to control the engine fuel economy by controlling the transmission. The 80 series, and the early 100 series too, have no such features.

The transmission control logic is very simple; it'll operate without the combination meter connected. The TCM doesn't "see" the meter at all; that's there only for you. That's why there are 2 speed sensors.

1st question (and I almost hate to ask this one): did the transmission operate properly before any work was performed? If not, what was/were the problem(s)?
2nd question: what are you calling the "VSS"? The vehicle speed sensor? If so, which one? There is one for the speedometer (the number 1 speed sensor) and one for the TCM (the number 2 speed sensor). I assume it's number 1? (just trying to make sure we're using the same words for the same parts, not picking at all)
3rd question: what work was performed on the transmission and shift linkage, prior to the problem you now have? Was the transmission/shift linkage removed?
4th question: when you inspected the pigtails (sub–harnesses), was the inspection limited to a visual check, or did you verify that the harness(es) had continuity from end to end?
5th question: were you able to verify that the solenoids are actually working? You can bench test them.

And, finally, this from the service manual:

I add this just to say that, since the A442F is not fully electronically controlled, you may have more than one fault.

IF the problem is a shift control problem, meaning the transmission will not shift from 1st the 2nd, it could be the solenoid and it could be the spool valve, and it could be both.

However, if the shift problem is a linkage problem, you may have both a pigtail error and a simple mechanical mis–adjustment.

 

[HejsanKwaheri]

To be clear about the operation of the A442F transmission: there is no "limp mode". The transmission either works or it doesn't. The TCM (transmission control computer) has no special programming for limiting the operation under any conditions. This is true for every 80 series Land Cruiser. "Limp mode" is a safety feature built into late model computers which operate to control the engine fuel economy by controlling the transmission. The 80 series, and the early 100 series too, have no such features.

The transmission control logic is very simple; it'll operate without the combination meter connected. The TCM doesn't "see" the meter at all; that's there only for you. That's why there are 2 speed sensors.

1st question (and I almost hate to ask this one): did the transmission operate properly before any work was performed? If not, what was/were the problem(s)?
2nd question: what are you calling the "VSS"? The vehicle speed sensor? If so, which one? There is one for the speedometer (the number 1 speed sensor) and one for the TCM (the number 2 speed sensor). I assume it's number 1? (just trying to make sure we're using the same words for the same parts, not picking at all)
3rd question: what work was performed on the transmission and shift linkage, prior to the problem you now have? Was the transmission/shift linkage removed?
4th question: when you inspected the pigtails (sub–harnesses), was the inspection limited to a visual check, or did you verify that the harness(es) had continuity from end to end?
5th question: were you able to verify that the solenoids are actually working? You can bench test them.

And, finally, this from the service manual:
View attachment 4126440
View attachment 4126439
I add this just to say that, since the A442F is not fully electronically controlled, you may have more than one fault.

IF the problem is a shift control problem, meaning the transmission will not shift from 1st the 2nd, it could be the solenoid and it could be the spool valve, and it could be both.

However, if the shift problem is a linkage problem, you may have both a pigtail error and a simple mechanical mis–adjustment.

Thank you for the education and detailed response.
1. Transmission worked with no issues prior to removal. I was unable to activate the cruise control a few months before I began my restoration. No work has been done on the transmission.
2. I replaced both sped sensors with oem sensors while the transmission was out.
3. I took the transmission in to a transmission shop to inspect it while I focused on the engine overhaul. They inspected the solenoids but I will verify if they bench tested them. I measured linkage before removing the transmission from the vehicle. Upon installation I replaced the linkage grommets. Shifts smoothly mechanically and lines up with indicators on the console.
4. Continuity was confirmed when pigtails were replaced. Have continuity on speed sensor 1 harness.
5. I will need to check with shop about any testing on the solenoids.

 

[HejsanKwaheri]

I still have some issues to iron out. I have low idle and it is very slow to respond to the accelerator. Cables have been adjusted to fsm specs. Accelerator cable was replaced(oem) The throttle position sensor was replaced(oem) and readings are according to the fsm. I am not finding any vacuum leak. Engine purrs and is timed correctly. Trying to go through process of elimination of what is causing low idle and inability to shift from 2nd to drive. It will rev up to 3200 and I can release the accelerator and it will shift into drive but shift back into second as the rpm lowers to 2800. Drive light dos not illuminate in the cluster but it may simply be a bulb.

 

[Malleus]

Good to know stuff! I'd ask the shop if they took any pictures when they finished their work, but before they reinstalled the pan, which they had to remove to access the solenoids.

While you're waiting for them, try the manual shifting test in the service manual. If you don't have one, download the 1994. Yes, I know you said yours was a '93, but you didn't specify the build month –anything after 09/93 is a '94 –, and the '94 version is well bookmarked (it's mine and I use it frequently).

 

[Malleus]

I still have some issues to iron out. I have low idle and it is very slow to respond to the accelerator. Cables have been adjusted to fsm specs. Accelerator cable was replaced(oem) The throttle position sensor was replaced(oem) and readings are according to the fsm. I am not finding any vacuum leak. Engine purrs and is timed correctly. Trying to go through process of elimination of what is causing low idle and inability to shift from 2nd to drive. It will rev up to 3200 and I can release the accelerator and it will shift into drive but shift back into second as the rpm lowers to 2800. Drive light dos not illuminate in the cluster but it may simply be a bulb.

OK, there are several problems here, so I'm going to address them one by one.

1st the engine idle: is this behavior hot or cold, or both? The solution differs by what the engine operating temperature is.

2nd, the combination meter display: there are exactly, and only two reasons (assuming the flex board is intact) – the bulb is out, which I doubt, or the connection between the engine and transmission harnesses isn't making contact. Are your backup lights working? If not, the problem is most likely in the joining connectors. They're above the starter.

3rd, the transmission shifting: now I understand it'll shift from 1st to 2nd, but not 2nd to 3rd (drive)? Does it shift from P to R correctly?

 

[HejsanKwaheri]

Good to know stuff! I'd ask the shop if they took any pictures when they finished their work, but before they reinstalled the pan, which they had to remove to access the solenoids.

While you're waiting for them, try the manual shifting test in the service manual. If you don't have one, download the 1994. Yes, I know you said yours was a '93, but you didn't specify the build month –anything after 09/93 is a '94 –, and the '94 version is well bookmarked (it's mine and I use it frequently).

Thanks. Build date is 5/93 and I have the service manuals. I will see where that manual test is at and perform that this week. I will keep you posted and thanks for the help.

 

[Malleus]

AT-28 in the 1993 manual.

 

[HejsanKwaheri]

OK, there are several problems here, so I'm going to address them one by one.

1st the engine idle: is this behavior hot or cold, or both? The solution differs by what the engine operating temperature is.

2nd, the combination meter display: there are exactly, and only two reasons (assuming the flex board is intact) – the bulb is out, which I doubt, or the connection between the engine and transmission harnesses isn't making contact. Are your backup lights working? If not, the problem is most likely in the joining connectors. They're above the starter.

3rd, the transmission shifting: now I understand it'll shift from 1st to 2nd, but not 2nd to 3rd (drive)? Does it shift from P to R correctly?

1. At startup idles at 250 am takes 45-60 with accelerator pedal depressed to get over 750-800. Once I have travelled 1-2 miles the temp is at 187-190(electronic guage installed). Even at operating temp it is very slow response to accelerator.
2. Backup lights work
3. Shifts from 1st to 2nd and only briefly from 2nd to 3rd if get rpms up to 3200 and release accelerator. At 2800 it shifts back down to 2nd.

 

[HejsanKwaheri]

I watched a video about testing hertz on back side of instrument cluster to confirm that readings coming up to the cluster. I will need to plug dash cluster back in and test while driving it seems.

 

[Malleus]

1. At startup idles at 250 am takes 45-60 with accelerator pedal depressed to get over 750-800. Once I have travelled 1-2 miles the temp is at 187-190(electronic guage installed). Even at operating temp it is very slow response to accelerator.
2. Backup lights work
3. Shifts from 1st to 2nd and only briefly from 2nd to 3rd if get rpms up to 3200 and release accelerator. At 2800 it shifts back down to 2nd.

OK, three thoughts to share:

1» the problem may be your idle air control (IAC) valve. There are two tests, described in the service manual. You need to perform both, and you have to remove it to do so. If yours is bad, try to find a used IAC from a 3rd gen Land Cruiser; the 2nd gen (yours) are NLA.
2» if your backup lights work, the problem with both shifting and the combination meter lights lie elsewhere; this junction connection feeds both the backup lights and the combo meter. No need to check your meter while driving. You can verify the flex board with a DMM and check the inputs at the ECM, under the glovebox; you need to get backprobes for this check (they look like very long needles). The details are also in the service manual. LMK if you can't find them.
3» sounds like the problem is the 2/3 solenoid. I'd look there first.

 

[HejsanKwaheri]

OK, three thoughts to share:

1» the problem may be your idle air control (IAC) valve. There are two tests, described in the service manual. You need to perform both, and you have to remove it to do so. If yours is bad, try to find a used IAC from a 3rd gen Land Cruiser; the 2nd gen (yours) are NLA.
2» if your backup lights work, the problem with both shifting and the combination meter lights lie elsewhere; this junction connection feeds both the backup lights and the combo meter. No need to check your meter while driving. You can verify the flex board with a DMM and check the inputs at the ECM, under the glovebox; you need to get backprobes for this check (they look like very long needles). The details are also in the service manual. LMK if you can't find them.
3» sounds like the problem is the 2/3 solenoid. I'd look there first.

Thanks. I was wondering about the iac but wanted to focus on the transmission first plus I didn’t want to take the throttle body off etc just yet. I performed the manual test you suggested and shifts fine which would lead us to an electronic issue. I will continue playing around with it between planting this week and keep you posted. Thank you so much for your assistance.

 

[HejsanKwaheri]

Thanks. I was wondering about the iac but wanted to focus on the transmission first plus I didn’t want to take the throttle body off etc just yet. I performed the manual test you suggested and shifts fine which would lead us to an electronic issue. I will continue playing around with it between planting this week and keep you posted. Thank you so much for your assistance.

Was able to remove idle air control and test. Resistance was 22.6-22.8. I was able to open and close the valve with voltage and grounding per fsm.

 

[Malleus]

Next item to check is the air inlet galley on the throttle body that feeds the IAC. Run a small wire through it and make sure it isn't full of carbon from the valve cover air recycling system. You can see the inlet for it on the passenger side (inlet) face of the throttle body. If it's plugged, it'll look like a black spot.

 

[HejsanKwaheri]

Thanks I will recheck that. I had performed a deep clean on the throttle body when I had it off during the rebuild. I spent a good hour playing with the throttle and accelerator cables yesterday moving them a turn at a time. Has improved somewhat. Idle is at 700 in park and reverse but drops to 250 when engaged into drive. It will slowly buildup rpms when in first and lowers back to 250 when shifting to 2nd and slowly builds back up. I will keep plugging away at it when I finish up with fieldwork this week. Thanks again.

 

[Malleus]

Idle at park is OK. Idle in gear is not. Check the linkage at the throttle body and make sure something is not FUBAR there. If that looks OK, check the transmission end of the throttle cable again, and make sure sure it's not pushing on the throttle body linkage when you shift gears.

 

[MVZ]

A friend had exactly the same problem with his dashboard speedometer: a resistor or transistor burned out, but the needle kept working. Inspect it carefully; you might be able to see what's burned out.

 

[HejsanKwaheri]

Idle at park is OK. Idle in gear is not. Check the linkage at the throttle body and make sure something is not FUBAR there. If that looks OK, check the transmission end of the throttle cable again, and make sure sure it's not pushing on the throttle body linkage when you shift gears.

I removed the throttle body yesterday to confirm that I had no issues with that. I ran through the fsm settings for the tps again. Th only issue I had was when at 0mm or when throttle lever is closed and touching the adjusting nut I get no ohms where the fsm has a range. I placed the feeler guage between the lever and adjusting screw and set the tps at the deflection point. I will see if helps with my issues.

 

[HejsanKwaheri]

I have gotten to the point that I am absolutely buffaloed on this ignition/transmission. My guy tells me it is dealing with the tps, maf, or electrical for the transmission. Are there any members in SW Kansas or mechaics that are salty with this vehicle? I have asked around and most shops just shrugged their shoulders. The local Toyota shops admit that their mechanics are younger than my 80. Thanks.

 

[Malleus]

Have you asked in the local clubhouse?