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Discussion Starter #1
Last night driving home from work I noticed my 05 balt 2.2L automatic accelerate very sluggish when at a full stop. After doing some test drives it seems that my car is not shifting down into first gear. Any idea what could cause this all of the sudden? Solenoid? Low fluid? Bad fluid?
 

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Solenoid probably, this can all be checked with a tech2.
 

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Discussion Starter #3
I'm bringing it to a transmission specialist today and he said they will drive it and scan it for free. I'm worried the scanner will come up nothing because I reset the battery last night to see if the car would feel any change. Is there anything type of driving or length of driving I can and should do before I bring the car to the shop? Much appreciated!!!


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Did you check the TCM fuse?

 

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Discussion Starter #5
Yes it is not burnt out and the terminals have what look like scrape marks from being inserted. I will go take a photo.


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---------- Post added at 09:03 AM ---------- Previous post was at 08:51 AM ----------


 

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All that's left is a broken wire or a bad 1-2 solenoid.

Electrical Function Check
Perform this check first, in order to ensure the electronic transmission components are connected and functioning properly. If these components are not checked, a simple electrical condition could be mis-diagnosed.

Connect the scan tool.
Ensure the gear selector is in PARK and set the parking brake.
Start the engine.
Verify that the following scan tool data can be obtained and is functioning properly.
Refer to Control Module References for typical data values. Data that is questionable may indicate a concern.

• Engine Speed

• Transmission input speed, turbine

• Transmission output speed

• Vehicle speed

• TFP manual valve position switch

• Transmission range

• Commanded gear, current gear

• PC solenoid reference current

• PC solenoid actual current

• PC solenoid duty cycle

• Brake switch

• Engine coolant temperature

• Transmission fluid temperature

• Throttle angle

• Ignition voltage

• 1-2 shift solenoid

• 2-3 shift solenoid

• TCC solenoid duty cycle

• TCC slip speed

Monitor the brake switch signal while depressing and releasing the brake pedal. The scan tool should display:
• Closed when the brake pedal is released.

• Open when the brake pedal is depressed.

Check the garage shifts.
6.1. Apply the brake pedal and ensure the parking brake is set.

6.2. Move the gear selector through the following ranges:

6.2.1. PARK to REVERSE

6.2.2. REVERSE to NEUTRAL

6.2.3. NEUTRAL to DRIVE

6.3. Pause 2 to 3 seconds in each gear position.

6.4. Verify the gear engagements are immediate and not harsh.

Important: Harsh engagement may be caused by any of the following conditions:

• High idle speed. Compare engine idle speed to desired idle speed.

• Commanded low PC solenoid current. Compare PC solenoid reference current to PC solenoid actual current.

• A default condition caused by certain DTCs that result in maximum line pressure to prevent slippage.


Important: Soft or delayed engagement may be caused by any of the following conditions:

• Low idle speed. Compare engine idle speed to desired idle speed.

• Low fluid level.

• Commanded high PC solenoid current. Compare PC solenoid reference current to PC solenoid actual current.

• Cold transmission fluid. Check for low transmission fluid temperature.


Monitor transmission range on the scan tool.
7.1. Apply the brake pedal and ensure the parking brake is set.

7.2. Move the gear selector through all ranges.

7.3. Pause 2 to 3 seconds in each range.

7.4. Return gear selector to PARK.

7.5. Verify that all selector positions match the scan tool display.

Check throttle angle input.
8.1. Apply the brake pedal and ensure the parking brake is set.

8.2. Ensure the gear selector is in PARK.

8.3. Monitor throttle angle while increasing and decreasing engine speed with the throttle pedal. The scan tool throttle angle should increase and decrease with engine speed.

If any of the above checks do not perform properly, record the result for reference after completion of the road test.

Upshift Control and Torque Converter Clutch (TCC) Apply
The TCM calculates the upshift points based primarily on two inputs: throttle angle and vehicle speed. When the TCM determines that conditions are met for a shift to occur, the TCM commands the shift by closing or opening the ground circuit for the appropriate solenoid.

Perform the following steps:

Refer to Shift Speed table in this section and choose a throttle position of 10%, 25% or 50%. All throttle angles shown should be tested to cover the normal driving range.
Monitor the following scan tool parameters:
• Throttle angle

• Vehicle speed

• Engine speed

• Commanded gear

• Slip speed

• Solenoid states

Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle using the chosen throttle angle. Hold the throttle steady.
As the transmission upshifts, note the vehicle speed when the shift occurs for each gear change. There should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded gear change.
Compare the shift speeds to the Shift Speed table. Refer to Shift Speed . Shift speeds may vary slightly due to transmission fluid temperature or hydraulic delays in responding to electronic controls.
• Note any harsh, soft or delayed shifts or slipping.

• Note any noise or vibration.

Repeat steps 1 through 6 to complete all throttle angles.
Important: This transmission is equipped with an electronically controlled capacity clutch (ECCC). The pressure plate does not fully lock to the torque converter cover. Instead, the pressure plate maintains a small amount of slippage, approximately 20 RPM, in SECOND, THIRD and FOURTH gears, depending on the vehicle application. ECCC was developed to reduce the possibility of noise, vibration or chuggle caused by TCC apply. Typical apply speeds are 49-52 km/h (30-32 mph) in THIRD gear and 65-73 km/h (40-45 mph) in FOURTH gear. Full lockup is available at highway speeds on some applications.

Important: The TCC will not engage until the engine is in closed loop operation and the vehicle speed is as shown in the Shift Speed table. Refer to Shift Speed . The vehicle must be in a near-cruise condition, not accelerating or coasting, and on a level road surface.

Check for TCC apply in THIRD and FOURTH gear.
• Note the TCC apply point. When the TCC applies there should be a noticeable drop in engine speed and a drop in slip speed to below 100 RPM. If the TCC apply can not be detected:

- Check for DTCs.

- Refer to Torque Converter Diagnosis .

• Refer to the Shift Speed table for the correct apply speeds.

• Lightly tap and release the brake pedal. The TCC will release on most applications.

Part Throttle Detent Downshift
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to 64-88 km/h (40-55 mph) in FOURTH gear.
Quickly increase throttle angle to greater than 50%.
Verify the following:
• The TCC releases

• The transmission downshifts immediately to THIRD gear

Full Throttle Detent Downshift
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to speeds of 64-88 km/h (40-55 mph) in FOURTH gear.
Quickly increase throttle angle to 100% (WOT).
Verify the following:
• The TCC releases

• The transmission downshifts immediately to SECOND gear

Manual Downshifts
The shift solenoid valves do not control the 4-3 manual downshift. The 4-3 manual downshift is hydraulic. The 3-2 and 2-1 manual downshifts are electronic. The solenoid states will change during, or shortly after a 4-3 downshift is selected.

Manual 4-3 Downshift
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to 64-88 km/h (40-55 mph) in FOURTH gear.
Release the throttle while moving the gear selector to THIRD.
Verify the following:
• The TCC releases

• The transmission downshifts immediately to THIRD gear

• The engine slows the vehicle

Manual 4-2 Downshift
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to 64-72 km/h (40-45 mph).
Release the throttle while moving the gear selector to SECOND.
Verify the following:
• The TCC releases

• The transmission downshifts immediately to SECOND gear

• The engine slows the vehicle

Manual 4-1 Downshift
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to 64 km/h (40 mph).
Release the throttle while moving the gear selector to FIRST.
Verify the following:
• The TCC releases

• The transmission immediately downshifts to SECOND Gear.

• The engine slows the vehicle.

• The transmission downshifts to FIRST gear at the calibrated speed, typically 48-64 km/h (30-40 mph).

Coasting Downshifts
Place the gear selector in the OVERDRIVE position.
Accelerate the vehicle to FOURTH gear with the TCC applied.
Release the throttle and lightly apply the brakes.
Verify the following:
• The TCC releases

• Downshifts occur at speeds shown in the Shift Speed chart. Refer to Shift Speed .

Manual Gear Range Selection
The shift solenoids control the upshifts in the manual gear ranges.

Perform the following tests using 10-15 percent throttle angle.

Reverse
With the vehicle stopped, move the gear selector to REVERSE.
Slowly accelerate the vehicle.
Verify that there is no noticeable slip, noise or vibration.
Manual First
With the vehicle stopped, move the gear selector to FIRST.
Accelerate the vehicle to 32 km/h (20 mph).
Verify the following:
• No upshifts occur

• The TCC does not apply

• There is no noticeable slip, noise, or vibration

Manual Second
With the vehicle stopped, move the gear selector to SECOND.
Accelerate the vehicle to 57 km/h (35 mph).
Verify the following:
• The 1-2 shift occurs

• The 2-3 shift does not occur

• There is no noticeable slip, noise, or vibration

Manual Third
With the vehicle stopped, move the gear selector to THIRD.
Accelerate the vehicle to 64 km/h (40 mph).
Verify the following:
• The 1-2 shift occurs

• The 2-3 shift occurs

• There is no noticeable slip, noise, or vibration
 

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Discussion Starter #7
Wow that is lengthy haha. The guy at the shop said he will test drive the vehicle and scan it. I disconnected my battery last night to see if there was any change in driving which there wasn't. Should I do some driving before I go to the shop or is the transmission stuff untouched?
 

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Won't affect anything, because he's not going to look for codes. He's going to electronicly activate each solenoid with his scan tool and see if they work, draw current and stuff like that. They are usually pretty good at figuring these transmission.
 

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Discussion Starter #9
Alright and if it is the 1-2 solenoid what is the replacement procedure on a 2005? I'm assuming they have to open the tranny which sounds expensive.
 

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No, just remove side cover adjacent to driver's side wheel and replace solenoid. A 2 hour job for an experienced mechanic.
 

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Discussion Starter #11
Does this service require draining the tranny fluid? If so should I use this opportunity to have the system flushed? I've never had it done before and I've heard people say never do it and some say to do it. The vehicle has 91000 miles and I bought it with 62000 miles 2 years ago and I've never had the tranny serviced.
 

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No, the oil is in the pan at the bottom, solenoid are on the side.
 

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Well even though I've heard nightmare stories about it. If the guy doesn't try to soak you, I would get the fluid changed but make sure he uses GM approved lubricants that meets or exceed.
 

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Discussion Starter #15
Ok. They are test driving it now.


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---------- Post added at 01:46 PM ---------- Previous post was at 01:28 PM ----------

He said it was going into first gear but the car is driving kind of sluggish. So I have no idea what's wrong.


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---------- Post added at 03:08 PM ---------- Previous post was at 01:46 PM ----------

He didn't hook it up to a scanner either because I disconnected my battery. But he said it feels like it's shifting correctly


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Discussion Starter #16
Well even though I've heard nightmare stories about it. If the guy doesn't try to soak you, I would get the fluid changed but make sure he uses GM approved lubricants that meets or exceed.

I just attempted to pull away from a curb on a decline after the car was sitting for a few hours and the engine revved to 3000rpms without acceleration and then the power went to the wheels. Took about a second - second and a half for the power to get to the wheels.


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---------- Post added at 10:45 PM ---------- Previous post was at 09:46 PM ----------

Well even though I've heard nightmare stories about it. If the guy doesn't try to soak you, I would get the fluid changed but make sure he uses GM approved lubricants that meets or exceed.
I just came across a thread on another forum where the person had similiar issues as me and posted a dashcam video. This is pretty much what it is like with my car.

 

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Hmm. My friend had a similar issue with a different car. It ended up being the throttle position sensor. I'm not sure if our car works the same, or even has a throttle position sensor, but it's an idea

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---------- Post added at 09:52 AM ---------- Previous post was at 09:49 AM ----------

Ok we do have the sensor, but it turns out your best bet is to replace the throttle body on our cars, if that is your problem. It should throw a code though

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Can't help you without having the car in my hands, sorry! But like other people have mentioned it looks like your throttle actuator is not responding to ECM commands. But you should get a code unless the ECM fuse is burnt or ign 1 fuse that supplies these sensors.
 
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