transmission locked in park

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#1
I work with a family that has a ‘98 Grand AM SE 2. 4L (118,000 miles) that last October experienced a significant ‘change’ with lockup in Park and restrictions on shifting. The family has since been using the unlock lever beneath the shifter to retain use of the car.

Before the ‘change’, the car had run well and shifting was normal. However, for a year or so before the ‘change’, there were a variety of DTCs that floated in and out . . inconsistency that we called ghosts because of a lack of a pattern. The ghost period began with P1870 with the longest interval of no DCT - 5 months. Then P0420/0422 started (no P1870) over a month then stopped. 3 months later P0442 started and P1870 reoccurred. 2 months later (Oct ‘11) the ‘change’ occurred. The DTCs from newest to oldest were: P0442, P0740, P0753, P0758, P01870. The ERLS 20 amp fuse was blown. Replacing the fuse and re-starting immediately produced P0740; the fuse didn’t immediately blow but did over time. In 2005, the transmission was rebuilt.

My question is . . does anyone have a thought on where to look for the short? Is this something that should go to a shop? The family’s resources are very limited.
 
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#2
I do not often post in TRANS but seeing no reply in several days I will try to help.

A load of electrical issues... I will ask -is there remote starter? aftermarket alarm? OR any other modifications... no sense looking at a wiring dia if they are present.

do you have some wiring diagrams? ie the brake trans interlock,

Start easy simple try looking at the - Range select switch, Brake switch its multi switches, then the wiring to the transmission...
 
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#3
kev2 . . thanks for responding.

I have never seen any electrical modifications . . definitely no remote start or alarm.

Yes, I have access to electrical diagrams thru alldatadiy. I located (today) the wiring diagram for the BTSI. Power is from the ERLS 20A fuse thru '439' to the transaxle range switch thru '275' to the brake switch and on to the BTSI/shift lock via '1135' and then to ground.

I have printed, in the past, a few diagrams beginning from the ERLS fuse thru '439' but I haven't seen how they connect together. I noticed today (which I hadn't before) on one diagram, the '439' goes to the EVAP cannister vent solenoid and purge valve. Previously, I had focused on another diagram showing the ERLS fuse thru '439 to the automatic transaxle (TCC and shift solenoids). I have never dealt with wire bundles before or short trouble shooting.
 
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#4
it is not one wire that meanders all over - there are several leads from the one fuse (load side) in the fuse box, some will SPLICE off of a wire - often shown as S439 and would give location of splice i the better wiring diagrams...

I see the 20amp ERLS fuse supplies several components. Never easy...
I mentioned to ck several components to try - a place to start...range switch, and harness to Trans ....

Check the brake switch and reverse sw circits an easy place to have a short... pink wire

you want to check the transaxle sw and the plug at trans- makiing sure the PINK wire is not grounded,
often shaking the harness would cause the circit to ground...

use the attached dia - check the systems on the ERLS circuit- easier said than done as there are several
 

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billr

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#5
Like kev2. I am "out of my element" here in the Trans section, but will add: have you scanned for all codes; manufacturer-specific, pending, etc?
 
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I forgot to add my reasoning - as the hard break right now is in the BTSI start there,
 
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#7
kev2, billr thanks for coming back so fast.

I am a retired engineer with a $140 scanner so I suspect I don't get what you want in terms of codes. The first post covered the range of codes that I see.

I appreciate the guidance that the 'hard break' is at the BTSI. I will start there but it will take me till next week. I have to check in with the family etc. Another reason for thanks . . at the beginning of the P1870 occurrences, I ran across a rare/non typical solution that talked about a short in the dash . . it didn't make sense . . I didn't keep the reference. I don't understand the term 'hard break' but you have given me enough to proceed. Thanks
 

billr

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#8
What is bothering me is that the original trans only lasted 7 years, and same for the rebuild. It seems like there is some root problem that has never been found and corrected. How about contacting the shop that did the rebuild? No way is it going to be under warranty, but a reputable shop will at least listen to you and might have more insight about this type of trans; at least do a complete scan for trans codes. Keep refreshing this post and let's hope one of the trans experts here joins the thread.
 
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#9
hard break vs intermittent....
and to reinforce this case you cant even start or move (locked in park) vehicle...

P1870 is a common GM code - would NOT affect operation but may effect the other issues .... ???
 
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#10
I meet with the family on Monday to work on the car. I will ask where the trans was worked on. In 2005, they had the car at the Pontiac dealership and the bill was $2000+ as I recall. I believe that was primarily the trans but they also had the A/C checked . . it didn't work before or after.

Between '08 and '10, the church spent ~ $1200 replacing the water pump, radiator, and starter. Since that time I have ck'd the A/C and found . . disconnected vacuum controls . . system wouldn't hold a charge; replaced a window regulator to get cross draft; replaced master brake cylinder . . intermittent loss of brakes (true - experienced it). If we knew then what we do now . . . . I was hoping an alternative vehicle would materialize over the winter but it didn't. The goal now is to pass environmental testing by the end of June.
 

billr

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#11
Clarify, is it really stuck in Park and inop? A Pontiac dealership is probably gone, but try at the same building anyway. There may be many of the same people still there, with pride and sense of responsibility for the "old days". That's the way with my local Chevy place that morphed into a Honda dealership.

Edit: sometimes you do just have to "cut bait"...
 
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#12
I surmise you are volenteering at your church ..Something I have done, very rewarding, although I found getting tech information difficult.. Hopefully we can assist you with some.

I feel that the problem is electrical - with all the DTCs being on the circuit that you are blowing fuses on..
a coincidence maybe but before I would condem a transmission - There are common parts as mentioned for the interlock and trans codes.

I would appreciate if you restated the problem, symptons, DTC,s - if you have a scanner or a code reader...
Knowing if it can scan would get us access to some information... Also you have wiring diagrams ALLDATA?

taking a SWAG - if cruise control equiped does it operate?
 
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#13
Problem restatement: 'B' had driven to the library. On coming out, she started the car but it was locked in Park. The car was towed home. We got together after some homework . . we removed the cover over the shifter positioned on the console, located the white plastic teter/toter lever/switch below the shifter on the right side and adjacent to the PCM? Experiment showed that holding the lever in one position while using the other hand to shift out of Park worked and the shifter could move to what ever position was desired. Yes, the transmission is locked when the engine is turned off with the shifter in Park. This procedure is required each time the is started.

I have an Actron OBD II AutoScanner Model # CP9175. The data I retain are DTCs, I/M monitors, and Freeze Data. I would attach a spread sheet with recorded data but I haven't figured out how. MIL Status I don't record. I have never tried to collect real time data . . . the manual doesn't suggest I can. I can't test components.

I do have access to ALLDATA but their diagrams are a lot more piece meal than the complete diagram kev2 attached. Thanks for the reference.

I would prefer not to test cruise control at this time if it has it. The DTCs indicate we have intentionally lost access to TCC and 4th gear, defaulted to 3rd gear and inhibited 3-2 down shifts above 30 mph.
 

billr

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#14
Kev2, do you know, is this thing old enough to have a TCM separate from the ECM?

I agree, it sounds like an electrical issue outside of the trans itself. Try to find every electric harness connected to the trans and check them all the way. I assume this has a solenoid to unlock that "Park" lever, start with wiring there.
 
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#15
We met at 9am this morning to check out the BTSI. The scanner showed newest to oldest: P0440,P0758,P0440,P0740-freeze data trip, P0753, P0758. IP alarms were: Brakes, ABS, ck eng. After clearing DTCs and replacing ERLS fuse, engine was started, yielded P0740 and blown ERLS.

ALLDATAdiy info for finding the BTSI was sketchy and we did not locate it. Location was supposedly behind the steering column covers and boot. Those were removed and we were looking for the BTSI to consist of 1 connector and 5 leads and attached to ?? with 2 fasteners. Leads were - . 35 pink, . 8 LT Grn, . 8 DK Grn/wht, . 5 WHT, and . 8 BLK. The wire color combination we were looking for did not match anything we could see on the column. To the right 12" and back there was a white block with 2 connectors. One connector's leads had the colors plus a brown but the leads were small compared to the heavy gage leads around the column . . seemed to small for a 20 A circuit. Can you provide a better direction or a picture of the BTSI?
Thanks