GM Tech II Test Report Analysis

Tech 2 self tests verify that the Tech 2 scan tool is functioning normally. The self tests evaluate all critical areas of
the Tech 2 and display pass or fail messages for each subsystem tested. Self tests isolate user error from
system hardware failures. The self tests should be performed periodically to insure that the Tech 2 is
operating properly.
The Tech 2 must meet the following requirements in order to do a self test:

• Screen display must be fully readable
• Keypad must be operational

Begin the Tech 2 self-testing program by following these steps:

1. Press [ENTER] while viewing the Tech 2 start-up screen (Figure VI-1).
2. Select F3: Tool Options from the Tech 2 Main Menu (Figure VI-2).
3. Select F3: Self Test from the Tool Options menu (

PCB DIAGNOSTIC CHART

Test	Result	Solution
RAM/ROM	0 - Pass 1 - ROM read fail 2 - RAM read fail 3 - RAM write and read do not compare.	Record type of failure. Cycle Tech 2 power (press [PWR]) and retest. If problem persists, contact Customer Support.
RS-485 loopback	Pass Fail - Loopback may not be connected.	Check loopback connection. If problem persists, contact Customer Support.
RS-232 loopback	Pass Fail - Loopback may not be connected.	Check loopback connection. If problem persists, contact Customer Support.
Keypad	Test successful Keypad failed Exiting the test before all keys are pressed results in a failed keypad test	Cycle Tech 2 power and retest. If problem persists, contact Customer Support.
PCMCIA (Tests both card slots)	Card detected Card not present Fail	Check that card is inserted properly. Cycle Tech 2 power and retest. If problem persists, contact Customer Support.
Display controller (Contrast and characters)	User determines if display is correct	If the display shows a noticeable failure during tests, contact Customer Support
Sound transducer	User determines if sound transducer is working.	If no sound is emitted by repeatedly selecting Automated Test or Sound On, contact Customer Support.
Real-time clock	Time is displayed correctly. Invalid values are displayed for date, year, hour, minute, or second.	Reset clock. Cycle Tech 2 power and retest. If time is not retained, contact Customer Support.

VCI MODULE DIAGNOSTIC CHART

Test	Result	Solution
MUX (Multiplexer)	MUX A: S5 & S14 pass/fail MUX B: S1 & S3 pass/fail	If MUX A or B fails, cycle Tech 2 power and retest. If problem persists, contact Customer Support.
VCI adapter ID (performed only during selectable VCI test)	Recognized adapter Cannot identify adapter	If adapter fails, use a different adapter to make sure that the VCI correctly identifies the adapters. Cycle Tech 2 power and retest failed adapter. If adapter fails second test, contact Customer Support.
VCI ADC (Analog to digital converter)	Channel A - pass/fail Channel B - pass/fail	If channel A or channel B fail, cycle Tech 2 and retest. If problem persists, contact Customer Support.
Cross point	Pull up - pass/fail TPU5, TPU1, and TPU0 - pass/fail (results from selectable VCI test)	If a failure occurs, cycle Tech 2 and retest. If problem persists, contact Customer Support.
SIPO (Serial In Parallel Out)	Pass/fail for each area tested	If a failure occurs, cycle Tech 2 and retest. If problem persists, contact Customer Support.
DLC (Data Link Connector)	DLC1 - DLC2 pass/fail count DLC2 - DLC1 pass/fail count	If a failure occurs, cycle Tech 2 and retest. If problem persists, contact Customer Support.
CCD (Chrysler Collision Detection)	CCD - pass/fail CCD - loopback not connected	Connect loopback and retest if loopback not connected. If test fails, disregard results. Test is not for GM vehicles (other than Saab) at this time.
GND FET (Ground Field Effect Transistor)	GND FET - pass/fail	Check loopback adapter to make sure it is connected, cycle Tech 2 retest. If problem persists, contact Customer Support.
VCI HBCC (Hosted Bus Control Chip)	HBCC - pass/fail	If HBCC chip fails, cycle Tech 2 and retest. If problem persists, contact Customer Support.
VCI DUART (Dual Universal Asynchronous Receiver Transmitter)	Channel A - pass/fail Channel B - pass/fail	If channel A or channel B fail, cycle Tech 2 and retest. If problem persists, contact Customer Support.
VCI I/O 1 - I/O 16 Test	Pass/fail messages will be displayed for each of the I/O lines (results from selectable VCI test). If test fails, was loopback installed?	Once an error has been detected on one of the I/O lines, you can test the specific line by selecting F3 or F4 tests. If the test fails continuously or intermittently, contact Customer Support.
VCI loopback	Pass/fail message for each I/O loopback test.	For any failure, make sure the loopback is connected. Use F1: Check ID to verify that the loopback is found. Cycle Tech 2 and retest. If problem persists, contact Customer Support
VCI short L & M	Open I/O 7 - pass/fail Open I/O 9 - pass/fail Hi I/O 7 - pass/fail Hi I/O 9 - pass/fail Lo I/O 7 - pass/fail Lo I/O 9 - pass/fail	For any failure, cycle Tech 2 and retest. If problem persists, contact Customer Support.
VCI J1708	Internal transceiver - pass/fail Differential - pass/fail Differential - pass/fail (results from selectable VCI test)	For any failure, cycle Tech 2 and retest. If problem persists, contact Customer Support.
VCI TPU (Time Processor Unit)	TPU0 - pass/fail TPU1 - pass/fail TPU5 - pass/fail TPU12 & TPU15 - pass/fail (or not tested if no loopback) TPU13 & TPU14 - pass/fail (or not tested if no loopback)	For any failure, cycle Tech 2 and retest. If problem persists, contact Customer Support.
VCI level shifters	MUX A 2.5 V Hi - pass/fail MUX A 2.5 V Lo - pass/fail MUX A 5.0 V Hi - pass/fail MUX A 5.0 V Lo - pass/fail (results from selectable VCI test)	For any failure, cycle Tech 2 and retest. If problem persists, contact Customer Support

POWER SOURCE: DLC CABLE
Step 1: Does vehicle support power through DLC cable connection
exclusively? (If you are not sure, consult your service manual.)
Yes: go to step 2
No: Use alternate power
Step 2: Using a digital multi-meter (DMM), verify vehicle battery voltage. Is battery fully charged?
Yes: go to step 3
No: Charge battery.
Step 3: Verify connection at vehicle DLC connector for loose or damaged
pin(s).
Did you find a problem?
Yes: Repair connector. (Consult vehicle service manual.)
No: go to step 4
Step 4: 1. Disconnect DLC cable from vehicle.

2. Power on Tech 2 using alternate power source at DLC cable

power jack connection.
Did your Tech 2 power on?
Yes: Problem with vehicle. (Consult vehicle service manual.)
No: go to step 5
Step 5: Remove DLC cable from Tech 2 and attach alternate power supply at VCI power jack connection located at bottom of Tech 2. Does Tech 2 power on?
Yes: Replace DLC cable.
No: Problem with Tech 2. Contact Customer Support.
POWER SOURCE: CIGARETTE LIGHTER POWER CABLE
Step 1: 1. Unplug cigarette lighter power cable from DLC cable.

2. Using a digital multi-meter (DMM), verify voltage output at

cigarette lighter power cable power jack.
Do you have battery voltage output?
Yes: go to step 2
No: go to step 3
Step 2: 1. Remove DLC cable from Tech 2.

2. Plug in cigarette lighter power jack to the VCI power jack

connector located at bottom of Tech 2.
Does the Tech 2 power on?
Yes: Replace DLC cable.
No: Problem with Tech 2. Contact Customer Support.
Step 3: Using a DMM, verify voltage output at battery.
Do you have battery voltage output?
Yes: go to step 4
No: Charge battery.
Step 4: Disconnect cigarette lighter power cable from vehicle and verify
voltage output at vehicle cigarette lighter socket.
Do you have battery voltage output?
Yes: go to step 5
No: Problem with vehicle. Consult vehicle service manual.
Step 5: Check fuse in cigarette lighter power cable (refer to Figure VI-23).
Does fuse need replacing?
Yes: Replace fuse.
No: Replace cigarette lighter power cable.
POWER SOURCE: BATTERY POWER CABLE
Step 1: 1. Unplug battery power cable power jack from DLC cable.

2. Using a digital multi-meter (DMM), verify voltage output at

battery power cable power jack.
Do you have battery voltage output?
Yes: go to step 2
No: go to step 3
Step 2: 1. Remove DLC cable from Tech 2.

2. Plug in battery power cable power jack to the VCI power jack

connector located at bottom of Tech 2.
Does the Tech 2 power on?
Yes: Replace DLC cable
No: Problem with Tech 2. Contact Customer Support.
Step 3: Using a DMM, verify voltage output at battery.
Do you have battery voltage output?
Yes: go to step 4
No: Charge battery
Step 4: Check fuse(s) in battery power cable (refer to Figure VI-24).
Does fuse(s) need replacing?
Yes: Replace fuse(s).
No: Replace battery power cable.
POWER SOURCE: NAO OR UNIVERSAL POWER SUPPLY
Step 1: 1. Unplug NAO (or Universal) power supply jack from DLC cable.

2. Using a digital multi-meter (DMM), verify voltage output at

power jack.
Do you have battery voltage output?
Yes: go to step 2
No: Replace NAO or Universal power supply
Step 2: 1. Remove DLC cable from Tech 2.

2. Plug in NAO (or Universal) power supply power jack to the VCI

power jack connector located at bottom of Tech 2.
Does the Tech 2 power on?
Yes: Replace DLC cable
No: Problem with Tech 2.
Contact Customer
Support.
TIS2000 CD and USB Key for GM TECH2 GM Car Model:
http://www.chinacardiags.com/wholesale/tis2000-cd-and-usb-key-for-gm-tech2-gm-and-opel-car-model-706.html

Tech 2 Adapters: What are they & How to use?

What is a Tech 2 adapter:
There are a number of adapters are available for the Tech 2 scan tool which allow connection to many different vehicles. Specific adapters are included in the Tech 2 base kit depending upon Tech 2 configuration—NAO, International, Saab, Opel, Vauxhall, etc. Adapters not included in the base kit may be purchased separately from your tool distributor
Tech 2 full kit with all adapters:

Source: http://www.chinacardiags.com/wholesale/tech2-diagnostic-scanner-for-gm-saab-opel-suzuki-isuzu-holden-with-full-package.html
Tech 2 adapters list:
All adapters available for Tech 2:
SAE 16/19 Pin Adapter:
This adapter allows DLC connection to some 1994-1995 NAO vehicles and all NAO vehicles from 1996 onward.

NAO 12/19 Pin Adapter:
This adapter allows ALDL connection to some 1994-1995 NAO vehicles and all previous 1993 and earlier vehicles equipped with 12-pin ALDL connectors.

Opel 10/19 Adapter:
This adapter allows connection for current Opel vehicles with a 10-pin connector.

Saab 10/19 Adapter:
This adapter allows connection for current Saab vehicles with a 10-pin connector.

Opel / Isuzu / Geo 3/19 Adapter:
This adapter allows connection for Opel, Isuzu, and Geo vehicles that have a 3-pin horizontal connector.

Opel / Isuzu 3/19 Adapter:
This adapter allows connection for Opel and Isuzu vehicles with a 3-pin “T” connector.

In detail... look at the chart below.

How to use Tech 2 adapters with the main unit:

1. VCI cable connector (26-pin connector)
2. Various vehicle adapters
3. DLC cable (19-pin connector end)

Tech 2 User Manual:
http://www.chinacardiags.com/wholesale/tech2-diagnostic-scanner-for-gm-saab-opel-suzuki-isuzu-holden-with-full-package.html

How to replace GM Tech2 DC-DC converter

Thread: GM Tech2 scan tool DC-DC converter replacement / No power on repair
If your thinking about a TECH 2 or have one that died like mine, this may help fix it.

https://www.facebook.com/obd2.diagnostics/videos/595347837467475/?t=0

This video goes over one possible source for a dead Tech2 scan tool that fails to power up when switched on. The video is aimed at various Chinese knock-off models of the GM Tech2 clone, but the repair would be applicable to an original OEM HP, Vetronix, or Bosch manufactured GM Tech2 as well. The repair involves replacement of the isolated DC/DC 5VDC power converter on the main logic board in either case. However, if you perform this repair on a genuine original Tech2, you will lose the ability for the unit to not restart during engine cranking due to normal vehicle battery voltage drop. The Chinese knock-offs were already missing this capability so no difference there (when you read about folks saying they fixed the unit restarting during engine cranking they just got lucky that the particular batch that the converter they bought came out of could handle dipping below 9VDC which is totally random and unpredictable). This is because the proprietary isolated DC/DC converter specified by GM is not available to the public and was custom modified to GM specifications so that it could handle as low as 7VDC input and still create isolated 5VDC output. The replacement isolated DC/DC converter parts available to the public require a minimum of 9VDC to output the same 5VDC. Sometimes you might randomly get lucky and one will go below 9VDC, but impossible to predict at purchase time. You could use a "cheap" non-isolated voltage converter replacement, but this is not recommended as it defeats the original protected isolated voltage circuit design by GM/HP.
btw. credits to DrShock

This from China OBD Diagnostic Online Supplier official blog:How to replace GM Tech2 DC-DC converter