Symptom Related Diagnostic Procedures

Symptom
- Possible cause(s)

Limp-in mode-No codes (must cycle key off and on to resume normal operation).
- 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

Transmission intermittently goes to 2nd gear, then back to OD with no codes.
- Intermittent TPS operation
- Intermittent connection
- Intermittent signal from TPS (Replace TPS)
- Intermittent or corroded "direct battery" feed to TCM (pin 16) or intermittent "ground", "power ground" and/or "signal ground" to TCM. 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.
- Defective TCM

Harsh engagement from Neutral to Drive.
- Engine mounts
- Squeaky exhaust donut: Perception: Harsher engagement
- Quick learn performed without first shifting to D to purge air in UD circuit. Learned a high UD volume.
- Engine idle speed to high (Check IAC Motor)
- Sticky TPS
- UD clutch clearance too low (UD clutch volume will not learn to compensate)
- High driveline backlash
- High spline clearance on driveshaft(s)
- Failed differential pinion pin

Delayed engagement from Neutral to Drive.
- Low fluid level
- Torque converter draindown-(normal 2 or 3 seconds with extended engine off time)
- Incorrect PRNDL code in "D" position
- Clogged oil filter
- Faulty oil pump
- 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

Delayed engagement from Neutral to Reverse.
- 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
- 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

Harsh engagement from Neutral to Reverse.
- Engine mounts
- Squeaky exhaust donut
- TPS sticking open
- Engine idle speed too high (Check IAC Motor)
- Incorrect PRNDL code in reverse
- High driveline backlash
- High spline clearance on driveshaft(s)
- Failed differential pinion pin

Poor Shift Quality.
- Defective engine mounts
- Deteriorated oil
- Worn clutches
- Intermittent clutch seal leakage (possible heat set failure)

Erratic shifting
- Engine performance
1. Sticky TPS
2. Stuck AC motor
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 temp too high above 110° C (230° F) or too low (below 66° C (150° F)
- Worn or faulty clutches
- Intermittent clutch seal leakage (possible heat set failure)

Drives in Neutral
- 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

Drags engine
- Worn or welded clutches
- Gear train failure

Stalls engine
- Defective solenoid (stalls engine by engaging torque converter lock-up clutch)
- Failed torque convener (stalls engine by engaging torque converter lock-up clutch)
- Stuck solenoid switch valve (stalls engine by engaging torque converter lock-up clutch)

Grating, scraping, or growling noise.
- Drive plate cracked or bent
- Failed pump bushing (may also set TCM code 38)
- Differential pinion pin failure
- Geartrain planetary failure

Buzzing noise.
- Clogged oil filter (may also set TCM code 35)
- Low fluid level
- Valve body malfunction or leakage

Buzzing noise during shifts only.
- Normal solenoid operation
- Solenoid sound cover loose

Transaxle overheats.
- High fluid level
- Transmission not operating in FEMCC - See symptoms for no EMCC engagement
- Transmission not shifting into D - See Symptoms for No Upshift Into Overdrive
- Engine overheat
- Engine idle speed too high
- Insufficient clutch plate clearance (should set code 60, 61, or 62)

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

No upshift into Overdrive.
- Engine coolant temperature too low
- Failed Engine Coolant Temperature Sensor - Check PCM DTC's
- TCM "OD off" circuit connected to brake switch wire
- Overdrive and/or 2-4 clutch or accumulator seals intermittent leakage
- Overdrive off switch or circuit shorted to ground
- Defective overdrive off switch

No Electronically Modulated Converter Clutch (EMCC) engagement.
- Engine coolant temperature too low
- Failed Engine Coolant Temperature Sensor - Check PCM DTC's
- Brake light switch misadjusted (indicating "brake on" when brakes are not on)

Harsh downshift.
- Engine performance
1. Sticky TPS
2. Stuck IAC motor (high idle speed)
3. Engine coolant temperature too low
- Defective solenoid assembly
- Valve body malfunction
- 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)

High shift efforts.
- Damaged shift linkage
- Sticky manual valve
1. Bore distorted - check for proper transfer plate to valve body screw
2. Bent manual valve lever (valve body pilot on manual lever)

Torque converter shudder [56-66km/h (35-41mph)] and/or harsh EMCC engagement.
- Failed (burnt) oil
- Worn pump bushing (slips in FEMCC, also sets code 38)
- Torque converter disc failure (slips in FEMCC, also sets code

Hard to fill: Oil blows out of filler tube.
- Restricted transmission vent
- Loose valve body
- Clogged or misinstalled filter

Engine misfire.
- Engine performance (see Powertrain Diagnostics Manual)
- Drive plate cracked or broken

Heavy throttle liftfoot clunk or tip in/tip out clunk.
- Engine mounts
- Squeaky exhaust donut
- Sticky TPS (Transmission will not upshift or unlock TCC)
- High driveline backlash
- High spline clearance on driveshaft(s)
- Failed differential pinion pin
- Loose transmission mounts
- Defective half shafts

No reverse (no fault code, sense circuit sees excessive vehicle at speed at stop).
- Vehicle speed sensor circuit indicates vehicle speed over 13km/h (8mph) due to circuit failure or external interference.