I have had some issues with my Trailblazer codes P1870 P0302 P0440. The car has had some issues while driving up hills no power and the transmission seems to not catch when it should.

There isn't a code P01871 , nor P1871 . DTC - P1870
The powertrain control module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +50 RPM.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.


Your best bet ,take your vehicle to a qualified repair shop.
Bronze material found in the transmission oil pan may indicate stator shaft bushing wear. If bushing wear is suspected, inspect the stator shaft and the input, turbine, shaft for damage.
• Refer to Symptoms - Automatic Transmission for more information.

P1870 ! not P01870
DTC P1870 Transmission Component Slipping (Buick Built Before 6/17/97)
DTC P1870 Transmission Component Slipping (All Other Applications)
Circuit Description
The Powertrain Control Module (PCM) monitors the Torque Converter Clutch (TCC) slip by calculating the difference between the engine speed and the transmission output shaft speed.
If the PCM detects an excessive amount of slip when the TCC is engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.

Code P1870...What does it mean??? - GM Forum - Buick, Cadillac ...

www.gmforum.com > ... > 1992-199
Jun 9, 2005 - Location: Bloomington-Normal, IL 1997 SE ... Default Code P1870...What does it mean??? I got a CE light the other day, and this is the code that was read word for word: P1870 ... No TCC solenoid electrical DTC P0740 ... Code P1870 & Speedometer error, Hi_tork, 1992-1999, 4, 10-16-2011 04:08 PM.

DIYer? I recommend a repair manual from your auto parts store. It should provide a complete list of all error codes and likely repair methods. Otherwise find a competent repair shop, or your dealer. I googled your error code This is just one of the answers: http://repairpal.com/check-engine-light-with-code-p1870-057
I am sure you can do a better search since you know far more about the issues.

P1870 generally means that the transmission is slipping. P0420 relates to an issue with a vehicles catalytic converter. To know specifically what each code is, as it relates to your vehicle, you should take it to a local auto-part store (like AutoZone and have them pull the codes off of your vehicle. At auto part stores, they generally do this service for free and it is pretty quick. Regards ~ JD

You can replace the transmission valve body as per the instruction or install a new TCC apply valve kit. However the installation requires for the valve body to be removed and honed out by a special tool. I wouldn't recommend this procedure unless you have the proper tools and the know how about the inner workings of the automatic transmissions.

#01-07-30-023B: Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body) - (Mar 22, 2002)
Subject: Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
Models: 1996 Buick Roadmaster
1996 Cadillac Fleetwood
1999-2000 Cadillac Escalade
1996-2000 Chevrolet Camaro, Corvette
1996-2000 Pontiac Firebird
1996-2000 Chevrolet and GMC Light Duty Truck Models
1996-2000 Oldsmobile Bravada
with 4L60-E Automatic Transmission (RPO M30)
Built Prior to January 15, 2000 (Julian Date 0015)

This bulletin is being revised to update VIN Breakpoint Date information and revise the Parts Information table. Please discard Corporate Bulletin Number 01-07-30-023A (Section 07 -- Transmission/Transaxle).

Condition: Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.

Diagnosis: Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

The scan tool may show a DTC P1870 set as a history code.

A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°C (200°F).

Cause: The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply.

Important:
• DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
• When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
• This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
• When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
• When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).

Correction: Install a control valve body with the revised TCC regulator and isolator valves. Refer to the Parts Information table below. These valves are used in all transmissions produced after January 15, 2000 (Julian Date 0015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.

Important: If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.
• Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
• The torque converter is not blue or overheated.
• The transmission fluid is not burned or has no burned odor.
• The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).

Keep us updated.

Cylinder 2 Misfire Detected po302 . Evaporative Emission Control System po440 The last digit on a misfire code indicates the cylinder number. A code P0302, for example, would tell you cylinder #2 is misfiring. Chances are the misfire is due to a weak ignition coil. Did you change the pcv valve? Remember to put the o-ring on the new one or this problem will happen.

P1870 relates to a torque converter clutch issue. The valve that controls the engagement of the transmission with the drive from the engine may be at fault. A transmission specialist will be able to shed more light on this fault for you. Hope this helps...

This GM service bulliten might apply to your vehicle:

TSB # 01-07-30-023A
Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
1996 Buick Roadmaster
1996 Cadillac Fleetwood
1996-2000 S10 Blazer
1999-2000 Cadillac Escalade
1996-2000 Chevrolet Camaro, Corvette
1996-2000 Pontiac Firebird
1996-2000 Chevrolet and GMC Light Duty Truck Models
1996-2000 Oldsmobile Bravada
with 4L60-E Automatic Transmission (RPO M30)
Built Prior to January 15, 1999 (Julian Date 9015)
This bulletin is being revised to update the Parts Information

Please discard Corporate Bulletin Number 01-07-30-023 (Section 07 -- Transmission/Transaxle).
Condition
Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.
Diagnosis
Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.
The scan tool may show a DTC P1870 set as a history code.
A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°C (200°F).
Cause
The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply

Important
DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).

When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).
Correction
Install a control valve body with the revised TCC regulator and isolator valves. These valves are used in all transmissions produced after January 15, 1999 (Julian Date 9015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.

Important
If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.

Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
The torque converter is not blue or overheated.
The transmission fluid is not burned or has no burned odor.
The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments

P0440- EVAP Emission Control Sys Malfunction

Something unspecified is wrong with the evaporative emission system. Check vac lines. Could be a loose electrical connection. This code has a very vague description.


P0302- Cyl 2 misfire

Has the car had a tune up in the past few years? Check plugs and wires, test for spark. Maybe a compression test. This issue may cause the next code.


P0172- Fuel trim Bank 1 , too rich

I would clear up the misfire first, then this code might go away.


P1613- MIL Call-up circuit open/Short to B+

Check the wiring under & behind the dash and instrument cluster. There apparently is a wiring issue, or the dash itself is shorted