Or, the TCM flashes codes and methods are here.
Or, the PCM starting in 1997 shows scan codes errors as OBD2, P07xx when scanned? (only at the OBD2 scan port)
Basics:
First off , this A/T has 100s of failure classes, a huge list of symptoms in the FSM , unlike any M/T made. (factory service. manual)
Slips, shifts late, too early, no shifts, stuck in a gear, harsh shifts, noises? , slips? or called flare, won't down shift or will not do engine braking?
The transmission will shift late, if the engine power is too low. (same deal with stuck TV {kickdown} cable; end to end)
So, the engine is first, any time power to the rear wheels is lacking.
Fuses good, no DTC errors at all? from engine brain (ECU) or transmission brain (TCM).?
ATF levels ok?, filter clean.
TV cable not stuck.?
No engine DTC errors. (or a weak engine or an engine that bogs, or one that misfires.....)?
If the transmission slips that is always a top symptom and must be addressed next. (line pressure low)? stall test fails? (see fsm above for that)
Does manual mode shift all 3 gears 1,3,4, R ok? (will skip 2nd, in this mode only)
Does the transmission skip 2nd gear, that is called failsafe mode, it means the TCM is upset, it's seeing gross errors, why not scan it.?
The below is mostly about the valve body, (TCM shifted)
See the slide show.
How does my TCM work , how does it TALK to me?
The TCM 1989-96 is located highest point in dash above right need, p/n 38880-57B21
In 1997 the TCM brain was moved inside the ECU and renamed the ECU to PCM (they are now own module)
Warning, do not ever condemn the trans or TCM for errors if the transmission ground strap is missing, broken or corroded. A BIG STRAP there at crossmember.
The TCM, like all computers, (It has a micro-processor) is subject to the rules of hard logic.
It is subject to the classic computer "GIGO" factor: Garbage In , Garbage out.
That means , if the inputs are wrong, so will be the output (shifting wrong, in this case)
The Brain (TCM) controls this valve body , seen below: (Vastly more simple, than old pure hydramatic boxes) I say brain, in the tradition of Allen Turning.
The solenoids can be replaced with tranny in car ! or the Valve body removed, the TV cable connects on top, (hard to get)
The coils can be ohms tested "resistance" pan not removed (open coils read infinity)
OD lamp flashing?
What does this mean and how do I correct the problem. (OD flashing)
Below are some hints.
OD means the top overdrive gear. 4th (a solid OD lamp means that)
OD lamp off means NOT on OD gear.
OD flashing, means (OD engaged) means I'm (Tranny) in Trouble ! Please help.
The TCM is the transmission control module. This page is dediacated to the TCM.
The TCM is telling you it senses faults and has stored a non 12 DTC code in the TCM
If the OD lamp is burned out, the TCM can't warn you. Fix that now.
GM calls this box option M41. (RPO code on glove box door...) This is the 4wd version of the very common, A44DE (Aisin BorgWarner) used on many toyota and volvo's.
The 4wd name is 03-72LE. see that 72LE adapter plate dead center? bingo !
Fast facts on the TCM: (pre 1997 first)
The first rule on any 4sp is: (other than fluid checks, etc)
Key on, and toggle the OD switch , lamp on , then off, is good that lamp works, but if the lamp flashes in the ON position of the OD selection ,this means there are stored DTC codes (diagnostic trouble codes).
If the lamp is dead, it is burned out , replace it now.
To retreave stored codes you just need jumper clip wire. (1997 and newer a scan tool is needed)
The pre 97 cars, there is a diagositic jumper (under dash at steering column DTC)) and if there are stored DTCs the O/D lamp flashes.
On 97+ and newer cars the DTCs show up with a standard USA OBD2, scan tool as DTC P07xx errors. 07xx means TRANS issues.
Resetting the Dome fuse resets the TCM and ECU. (this action is harmless and is done to erase stored false or corrected DTCs)
Do not pull the main car battery, as that messes up the RADIO and ALARM (or other accessories you have added)
If the ECU is bad, or stuck in FAILSAFE mode, it may fail to talk to the TCM and may cause the TCM to make poor shifting choices. (delays, etc)
If the Engine never warms up (ECT sensor data) the TCM will not shift perfectly, as the TCM does use the ECT sensor to augment shift profiles . It might not engage OD 4th gear until engine is hot.
If the engine idle speed, is way too high (engine issues) , the neutral to Drive gear selection, will be harsh.
The TCM (transmission control module) actually shifts the car for you ! ( it's the Brains )
It also has diagnostics that run full time and can flash the light OD. Clue #1 ( a simple warning to you, please help me.. I'm sick.)
The TCM has a special Fail-SAFE mode, when sick, it skips 2nd gear. (clue# 2)
The TCM can be asked to flash out codes, just like the ECU (PCM) does on all pre 97's.
These coded flashes are DTC errors. (Diagnostic Trouble Codes.)
The TCM has many inputs, and some are shared with the EFI ECU, like Coolant temperature (ECT) and throttle position TPS and others.
The TCM shifts the transmission via the transmission solenoids (hydraulic /electric)
The shift points are determined 2 ways, the ECU and the TV cable.
The ECT allows the transmission to shift more gently during high RPM (2000RPM it can be or more, cold ) and when the ATF fluid is very cold and thick (viscous) the TCM compensates for this thicker ATF fluid.
You can see if the transmission is working ok, by driving with the TCM connector pulled, this makes the tranny box shift manually, but no 2nd gear here is normal. 1,3,OD and REV.
If the tranny 3 gears don't slip (flare) or do other odd effects as you shift the tranny is mostly good.
In manual mode all 3 forward gears most work (1,3,4) and none dead, or slips. If the 3rd gear selected, causes the trans to stick in 1st , this is serious transmission failure ( do a line pressure test next) see fsm.
The older TCM's like to have bad main filter capacitors inside, just like the ECU does.
Starting in 1997 you pull the connector (solenoid paths) on left side of tranny. There is no 1997+ actual TCM , the TCM moved to the PCM box.
The Sequence of events are:
The TCM sees the operator shift to drive, the TCM energizes soleniods #1 and not 2 , you then accelerates and the TCM watches, RPM of engine, VSS speed and throttle angles to shift.
Then at the correct moment, it shifts to 2nd by energizing solenoids 1 and 2 at the same time. this process continues up the gears, by selecting logic on just 3 wires to 3 solenoids. One solenoid is TCC lock up only.
The TCM UPON detection of a bad VSS2 tail shaft speed sensor, drops to fail safe, and then uses VSS1 in the speedo head for a backup, and skips 2nd gear
If by chance your speedo cable is snapped. with VSS2 dead. (both VSS are bad?) then you are now rewarded with dead tranny (stuck on 1st? when in Drive) The newers cars the VSS is on the trans, tail shaft housing end.
VSS1 (speed cluster sensor) is the crude backup sensor for VSS2 (high accurate sensor) (only early cars have 2 VSS sensors)
A bad TPS input can result in no passing gear feature (no kick down as does the cable... ) my theory is that the TPS and kick cable work in cooperation, for a faster better Kick down action.
More inputs: are:
The Tachometer input. (engine RPM) , ECT (coolant temp), Load signal the ECU sends LOAD data to the TCM (hills?) and 4 shifter demand signals.
The Brake switch , OD feature, and 4wd Low signal , and OD mode, kills OD feature also. (P/S switch performance ) keep in mind the TCM may watch 4wd activation and change or block top gear, or TCC lockup.
Seems TCM has to learn to shift, after a Dome reset, but try that, if you think shifting is too harsh. A short drive is all that is need, no magic or NASA engineers.
Some TCMs does learn the drivers habits. (and tunes for weight of car and towing a heavy load)
See the TCM wiring here.
TCM DLC errors, or flash codes. The OD lamp flashes error codes on demand by you 1992 to 1996 (USA)
The 1997 and newer SIDKICK, just connect up your OBD2 scan too here and scan, normal methods of getting TCM errors. (if there are no P07xx errors then the TCM is happy)
Prior to 1997 , you need to jump 2 pins seen below on the TCM DLC connector. (on the 1996 Suzuki J18 1.8L Sport , I'm not sure of color or location!)
DLC3 (tcm) a.k.a , The monitor coupler.
This is G16 engine car ,with DLC is located between drivers legs, under dash , near steering shaft.The wire colors above are Blue-Org and Blue. (TCM diag. pin wire colors) TCM pins 7 & 18 )
The steps for the yellow connector above, are below.
1992 to 1996(only) 1997 and newer cars, see listiing below.
- Place a jumper wire. ( a
jumper clip is needed ) at TCM diagnostic connector, under
steering
column)
- Key on (no start)
- Read
the OD lamp codes flashing code 12 is good code. see
the codes table below. (flash pause flash flash, long pause , repeats)
- Do this any time the OD lamps flashes , driving, or driver
agressively look for the OD lamp to act odd? then place the jumper to
get the ERRIR code.
- Read the manual and how these codes relate to real failures.(96' here)
One nice trick, that works well, is to drive all around town with the diagnostic jumper connected. (96 and older) (in 1997+ you must use OBD2 logging to do this, effectively)
Drive aggressively and on hills to see if the 12 Flashing cadence, ever changes to some other DTC code, even for a second. (or on the newer car, see if the SCAN tool shows P07xx errrors, driving)
Before you condemn any 4speed box.
Go to manual mode, and drive agressively, does tranny slip? or fail to shift? on demand by you?
Make sure the ECU is not throwing DTC errors for the engine or transmission codes.
Make sure the ECU in your car is the 4speed ECU and not a 5 Speed manual WRONG ECU/PCM in car.
Keep in mind a weak engine might feel like a bad transmission, after all if the engine power is limited how can the transmissions shift correctly.?
If the RPM on the tachometer rises fast and speed don't; that is called transmission SLIP.
TCM power button rules (shift points)
DLC means, Diagnositic Logic Connector: (they have many functions)
1: DLC for TCM above , flash codes
2: or a 1992 car , with RWAL , using same connector above (shared with TCM)
3: Under hood DLC for setting idle duty cycle, timing freeze, and if pre 96, engine error codes.
4:and the 1996 and newer under dash , OBD2 DLC. that works with a scan tool, for engine, or air bags, and ABS.
FLASH CODES: (or OBD2 codes)
Automatic transmissions are nothing trivial.
I'm 100% convenced the 4speed is far easier to diagnose than any 3speed and is more efficient. That 2nd Column is 1997+ OBD2 scan DTC errors. The left side is pure TCM in box, flash codes (OD flash codes)
The word Performance above means, poor transfer of power (slippage?). (the TCM knows input RPM and output RPM, so can see and discover bad performance.
The P codes above are for 96 and newer cars only.
MANUAL shifting , Magic manual mode testing per FSM.
HOW does MANUAL test mode work?
The early cars you just pull the TCM connector under the dash. (the connector has a LOCK, do not force it,)
Later cars, 97+ pull the actual side connector on the transmission casing. (the TCM is missing now, pulling the PCM connector now, kills the engine dead) so this is the new and alternate way.
Note 2nd gear is skipped in test mode and failsafe mode. (so you can't check for 2nd gear slippage, doing this)
Some Kick owners drive for a year, like this. (saving up cash toy buy , expensive valve body ,etc....?)
Below, is the 89-96 factor instructions.
The technican can do the above, drive car agressively and feel each gear, (not 2nd) to see if any slip, or flare are are dead. Some folks who live on flat ground , drive like this for years. (a dead TCM)
I use Limphome and Failsafe , interchangebly .
This chart below, is for test 1: (click image to Zoom it)
I can monitor the output of the TCM to see that it is shifting all gears. using LEDs, (All connectors are connected and I am side tapped in to the 2 lines.)
Test 2 is next , the manual drive box test.
As you can see, I unplugged the trans, side connector and then with pin connectors, connect my toggle switch box , per below.
Doing this test , this way I can shift all gears, and make sure they are working (ratio wise) and do not slip.
The 1997+ PCM is wired like this.
LAST and not the least, is the TV cable. (bad cable or seized/rusted, or snapped, can cause, late or early shifting (stuck out is late shifts) (aka passing gear, cable, or kickdown cable)
I have shown below the 2 ends of said cable.. (no more magic?) As one might expect valve 20 below does change line pressure and shift points.
The Cable just does 1 thing, it sends drivers right foot actions to the transmission kickdown valve, seen as I.D. #20 below. and spring #17. (this causes the transmission shift points to change)
To check (test) the cable, remove it from the TB, (throttle body bracket seen in photo 2 below )
Then pull its end ball, to remove all slack, then try to feel spring 17, you must be able to feel the spring wind up, from down in the box or the cable is bad. (or worse valve body failure)
The cable when old , plastic casing cracks, like most plastic does, and lets in water, and the cable rusts and jams up. (a comon failure) It can even stick in the out location causing full time late shifting and line pressure low.
You can see that the other end is a pain to reach, dropping the valve body, is step #1 on removing the cable bottom end. (the FSM for it is here)
requires dropping Valve body to replace cable . (or test if part 20 even spins?)
1996 and newer, OBD2 scan port for PCM (and TCM starting in 1997)J18 TCM evidence:
Note the blank pins, The blank pin are 1996 only , has and external (to ECU) TCM box.
In 1997 , Suzuki deleted the TCM box and moved its brains to inside the ECU. (both hardware and software moved to there and became only OBD2 scans now)
This drawing most clearly shows this fact.
Note the OD lamp pin A11. (as you can see the PCM now flashes the OD lamp, directly in 1997 on)
I will soon document the 1996 sport TCM wiring, and its secret jumper wire locations, colors and schematic,
I suspect the 1996 Sport lacks the old style TCM DLC connector.
The Russian drawing may help the blue-orange wire pin, jump it to black pin. Ignore illegal Russian OBD2 pin numbers...
Then this USA drawing 1996 J18 SPORT (I think this drawing is wrong, its really and Esteem J18) and the colors are wrong too.
e101
is DLC2 , and G14 is OBD2 , pin 9 (shared with air bag and
abs) One is serial data , I think and other is the diag request
pin..version V5 , 2-12-13 (rewrite, and dedicate this page totally to TCM ) added slide show and more tests. 5-15-2014.