7 Checking For Symptoms and Possible Causes

NOTE: For some transmission problems, there is no diagnostic trouble code set. Verify the problem or the customer complaint, and make sure that the transmission is experiencing the problem at this time.

Low battery voltage can cause many of the symptoms listed below. Check battery condition and repair as necessary before continuing.

SYMPTOM
1. Limp-in mode - No codes (must cycle key off and on to resume normal operation).
2. Transmission intermittently goes to 2nd gear, then back to OD with no codes.
3. Harsh engagement from Neutral to Drive.
4. Delayed engagement from Neutral to Drive.
5. Delayed engagement from Neutral to Reverse.
6. Harsh engagement from Neutral to Reverse.
7. Poor Shift Quality.
8. Erratic shifting.
9. Drives in Neutral.
10. Drags engine.
11. Stalls engine.
12. Grating, scraping, or growling noise.
13. Buzzing noise.
14. Buzzing noise during shifts only.
15. Transaxle overheats.
16. Harsh upshifts.
17. No upshift into Overdrive.
18. No EMCC engagement.
19. Harsh Downshifts.
20. High shift efforts.
21. Torque converter shudder (35 - 41 MPH) and/or harsh EMCC engagement.
22. Hard to fill; Oil blows out of filler tube.
23. All PRNDL selection lights "On" in all positions with engine running.
24. All PRNDL selection lights "On" in Park and Neutral gear positions.
25. All PRNDL selection lights "Off" in all positions with engine running.
26. All PRNDL selection lights "Off" accompanied by a "No Bus" message.
27. PRNDL selection lights out of sequence with shift lever position (with PRNDL and P/N switch).
28. Engine misfire.
29. Heavy throttle liftfoot clunk or tip in/tip out clunk.
30. No shifting in AutoStick mode.
31. No reverse (no fault code, sense circuit sees excessive vehicle at speed at stop).
32. Wrong fluid type.

NOTE: If any of these symptoms are occurring, refer to the following symptoms in this test for possible causes.

SYMPTOM:
Limp-in mode - No codes (MUST cycle key off and on to resume normal operation)

Possible Causes:
- See diagnostic procedure for Code 15
- Defective relay (most likely cause)
- Intermittent relay connection
- Intermittent B(+) splice to relay
- Intermittent Fused Ignition Switch Output Feed to TCM

SYMPTOM:
Transmission intermittently goes to 2nd gear then back to OD with no codes

Possible Causes:
- Intermittent TPS operation
> Intermittent connection
> Intermittent signal from TPS (Replace TPS)

- Intermittent or corroded:
> Fused ignition output
> Fused 8+ -Ground
Intermittent may not last long enough to set TCM code 12, this allows the TCM to power up and down, shifting the transmission between 2nd and normal operation without a fault. Performing Test 76 will check for these conditions.

- Defective TCM

SYMPTOM:
Harsh Engagement From Neutral To Drive

Possible Causes:
- Engine mounts
- Squeaky exhaust donut: Perception: Harsher engagement
- Quick learn performed without first shifting to OD to purge air in UD circuit. Learned a high UD volume.
- TCM software not up to date - check TSB
- Engine idle speed to high (Check AIS Motor)
- Sticky TPS
- UD clutch clearance too low (UD clutch volume will not learn to compensate)
- High driveling backlash
> High spline clearance on driveshaft(s)
> Failed differential pinion pin

SYMPTOM:
Delayed Engagement From Neutral To Drive

Possible Causes:
- Low fluid level
- Torque converter drain-down - (normal 2 or 3 seconds with extended engine off time)
- Valve Body - #1 ball check of L-R switch valve sticky
- Incorrect PRNDL code in "OD" position
- Clogged oil filter
- Faulty oil pump
- TCM software not up to date - check for latest TSB
- UD or LR seal leakage (possible heat set failure)
- Sticky accumulator seal rings
- Worn or broken reaction shaft seal rings(s)
- Worn reaction shaft support bushing
- Valve body malfunction or leakage

SYMPTOM:
Delayed Engagement From Neutral To Reverse

Possible Causes:
- Low fluid level
- Torque converter drain-down - (normal 2 or 3 seconds with extended engine off time)
- Incorrect gearshift control linkage adjustment
- Clogged oil filter (should set code 35)
- Incorrect PRNDL code in reverse
- Valve body malfunction - #1 ball check sticking or L-R switch valve sticking
- Faulty oil pump
- Worn or faulty reverse and/or L-R clutch(es)
- Low/reverse clutch or accumulator seal leakage
- Worn or faulty low/reverse retainer
- Worn or broken reaction shaft seal rings
- Hydraulic pressure too low

SYMPTOM:
Harsh Engagement From Neutral To Reverse

Possible Causes:
- Engine mounts
- Squeaky exhaust donut
- TPS sticking open
- TCM software not up to date - check for latest TSB
- Engine idle speed too high (Check AIS Motor)
- Incorrect PRNDL code in reverse
- High driveline backlash
> High spline clearance on driveshaft(s)
> Failed differential pinion pin

SYMPTOM:
Poor Shift Quality

Possible Causes:
- Defective engine mounts
- TCM not up to date - check for latest TSB
- Deteriorated oil - See TSB
- Worn clutches
- Intermittent clutch seal leakage (possible heat set failure)

SYMPTOM:
Erratic Shifting

Possible Causes:
- Engine performance
1. Sticky TPS
2. Stuck AIS motor
> On 93 -95 MY AS with 3.3 or 3.8L engine, #2 spark plug wire close to EATX harness (see TSB 08-07-94)
3. Intermittent fuel pressure
4. Engine coolant stays low too long
> Thermostat stuck open (Trans operating in overheat strategy)
> Defective coolant sensor and/or connector (check PCM DTC's)
5. Cooling fans inoperative

- Transmission overheating.
1. Normal operation in city traffic, stop and go traffic, stop and go traffic
2. Engine coolant tamp too high (above 230 degrees F) or too low (below 150 degrees F)

- Worn or faulty clutches
- Intermittent clutch seal leakage (possible heat set failure)

SYMPTOM:
Drives in Neutral

Possible Causes:
- Incorrect gearshift control linkage adjustment
- Underdrive clutch welded or insufficient clearance
- Overdrive clutch welded or insufficient clearance
- Reverse clutch welded or insufficient clearance
- Valve body malfunction or leakage

SYMPTOM:
Drags Engine

Possible Causes:
- Worn or welded clutches
- Gear train failure

SYMPTOM:
Stalls engine

Possible Causes:
- Defective solenoid (stalls engine by engaging torque converter lock-up clutch)
- Failed torque converter (stalls engine by engaging torque converter lock-up clutch)
- Stuck solenoid switch valve (stalls engine by engaging torque converter lock-up clutch)

SYMPTOM:
Grating, Scraping, or Growling Noise

Possible Causes:
- Drive plate cracked or bent
- Failed pump bushing (may also set TCM code 38)
- Differential pinion pin failure
- Gear-train planetary failure

SYMPTOM:
Buzzing Noise

Possible Causes:
- Clogged oil filter (may also set TCM code 35)
- Low fluid level
- Valve body malfunction or leakage

SYMPTOM:
Buzzing Noise-During Shifts Only

Possible Causes:
- Normal solenoid operation
- Solenoid sound cover loose

SYMPTOM:
Transaxle Overheats

Possible Causes:
- High fluid level/low fluid level
- Transmission not operating in FEMCC - See symptoms for no EMCC engagement
- Transmission not shifting into OD - Symptoms for No Upshift Into Overdrive
- Engine overheat
- Engine idle speed too high
- Insufficient clutch plate clearance (should set code 60, 61, or 62)
- Restricted fluid flow
- Insufficient coolant

SYMPTOM:
Harsh Upshifts

Possible Causes:
- Engine performance
1. Engine coolant temperature too low
2. Sticky TPS
3. Stuck AIS motor
- Failed (burnt) oil
- Worn or faulty clutches
- Clutch or accumulator seal leakage

SYMPTOM:
No Upshift Into Overdrive

Possible Causes:
- Engine coolant temperature too low
- Failed Engine Coolant Temperature Sensor (ECT)
Check PCM DTC's
- TCM "OD off" circuit connected to brake switch wire (cavity 49 in TCM connector, check TSB 18-24-95 or latest)
- Overdrive and/or 2-4 clutch or accumulator seals intermittent leakage
- Overdrive off switch open or circuit shorted to ground
- Defective overdrive off switch
- Overdrive Switch enabled and bulb burned out (FJ only)

SYMPTOM:
No EMCC Engagement

Possible Causes:
- Engine coolant temperature too low
- Failed Engine Coolant Temperature Sensor (ECT) - Check PCM DTC's
- Brake light switch misadjusted (indicating "brake on" when brakes are not on)

SYMPTOM:
Harsh Downshift

Possible Causes:
- On 93-95 MY AS with 3.3 or 3.8L engine, #2 spark plug wire close to TCM harness (see TSB 08-07-94)
- Engine performance
1. Sticky TPS
2. Stuck AIS motor (high idle speed)
3. Engine coolant temperature too low
- TCM software not up to date - check for latest TSB
- Defective solenoid assembly
- Valve body malfunction - #1 ball check or L-R switch valve sticking
- Clutch and/or accumulator seal leakage
- Underdrive clutch volume too high (4-3 coastdown only)
- UD clutch clearance too low (UD clutch volume will not learn to compensate)

SYMPTOM:
High Shift Efforts

Possible Causes:
- Damaged shift linkage
- Sticky manual valve
a. Bore distorted - check for proper transfer plate to valve body screw
b. Bent manual valve lever (valve body pilot on manual lever)

SYMPTOM:
Torque Converter Shudder (35-41 MPH) and/or Harsh EMCC Engagement

Possible Causes:
- TCM software not up to date - check for latest TSB
- Failed (burnt) oil
- Worn pump bushing (slips in FEMCC, also sets code 38)
- Torque converter disc failure (slips in FEMCC, also sets code 38)

SYMPTOM:
Hard to Fill: Oil Blows Out Of Filler Tube

Possible Causes:
- Restricted transmission vent
- Loose valve body
- Clogged or misinstalled filter

SYMPTOM:
All PRNDL Selection Lights "On" In Park and Neutral Gear Positions

Possible Causes:
- Wrong TCM for application
- Follow diagnostic procedure for TCM code 28
- Wiring or connectors
- Faulty Park/Neutral Switch, PRNDL switch. (Application dependent)
- Faulty manual lever assembly
- Start signal from ignition switch "on"

SYMPTOM:
All PRNDL Selection Lights "On" In All Positions With Engine Running

Possible Causes:
- Defective TCM
- Defective BCM
- Defective cluster
- CCD communication malfunction
- Loss of power to TCM (or BCM on LH, JA, and JX)
- Loss of ignition feed to TCM (or BCM on LO, JA, and JX)

SYMPTOM:
All PRNDL Selection Lights "Off" In All Gear Positions With Engine Running

Possible Causes:
- Normal transient position condition between gear selector positions
- Body controller malfunction on BCM equipped vehicles
- Faulty cluster

SYMPTOM:
All PRNDL Selection Lights "Off" Accompanied By A "No Bus" Message

Possible Causes:
- CCD communication malfunction

SYMPTOM:
Engine Misfire

Possible Causes:
- Engine performance
- Drive plate cracked or broken

SYMPTOM:
PRNDL Selection Lights Out Of Sequence With Shift Lever Position (with PRNDL and P/N switch)

Possible Causes:
- Wiring or connectors
- Faulty Park/Neutral switch or PRNDL switch
- Faulty manual lever assembly

SYMPTOM:
No Manual Upshift or Downshift in AutoStick Operation

Possible Causes:
- Incorrect TCM part number
- PRNDL will not light-up also
- Incorrect gearshift control cable adjustment
- Upshift or downshift sense circuits open
- Damaged connector(s)
- Damaged terminal(s)
- Faulty transmission control module (TOM)
- Bad ground at AutoStick switch
- No ignition feed to AutoStick switch

SYMPTOM:
Heavy Throttle Liftfoot Clunk or Tip in/Tip out Clunk

Possible Causes:
- Engine mounts
- Squeaky exhaust donut
- Sticky TPS (Transmission will not upshift or unlock TCC)
- High driveling backlash
> High spline clearance on driveshaft(s)
> Failed differential pinion pin
> Loose transmission mounts
> Defective half shafts

SYMPTOM:
No Reverse (No Fault Code. vehicle speed shown at stop

Possible Causes:
- Vehicle speed sensor circuit indicates vehicle speed over 8 mph due to circuit failure or external interference.