94 gmc 4.3 vin z 2wd standard 12 pin aldl connector code retrieval

What year an make vehicle ? Before 1996 you can do that on some make vehicles , not all ,GM cars mostly ! 1996 an above need scanner for all vehicle makes !

If your ALDL connector is a 16 pin (looks like an OBD2) but your GM vehicle is 95 or 94 then the only way to scan the codes is with a scanner. http://reddevilriver.com/aldl.html

You need someone with a scan tool or someone who knows how to retrieve the codes without a On 1983-94 models, the ALDL connector or Data Link Connector (DLC), located under the dash, and sometimes covered with a plastic cover labeled DIAGNOSTIC CONNECTOR, can be activated by grounding test terminal B . The terminal is most easily grounded by connecting it to terminal A (internal ECM ground), the terminal to the right of terminal B on the top row of the ALDL connector. Once terminals A and B have been connected, the ignition switch must be moved to the ON position with the engine not running.

1. Turn the ignition switch OFF .
2. The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition OFF and remove the jumper wire. Turn the ignition ON and confirm that light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
3. The code(s) stored in memory may be read either through counting the flashes of the dashboard warning lamp or through the use of a hand-held scan tool. If using the scan tool, connect it correctly to the ALDL.
4. After the terminals are connected, turn the ignition switch to the ON position, but DO NOT start the engine. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
5. After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.

The order of codes in the memory does not indicate the order of occurrence.

1. If there are no codes stored, but a driveability or emissions problem is evident, the system should be diagnosed by an experienced driveability technician.
2. If one or more codes are stored, record them. Refer to the applicable Diagnostic Code chart in this section.
3. Switch the ignition OFF when finished with code retrieval or scan tool readings.
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GM Bonneville/Eighty Eight/LeSabre 1986-1999
Reading Codes

• 1987-97 VEHICLES EXCEPT 1997 MODELS WITH 16-PIN DLC
• 197 VEHICLES WITH 16-PIN DLC AND ALL 1995-99 MODELS

Print

1987-97 VEHICLES EXCEPT 1997 MODELS WITH 16-PIN DLC

See Figures 1 and 2
Listings of the trouble for the various engine control system covered in this manual are located in this section. Remember that a code only points to the faulty circuit, NOT necessarily to a faulty component. Loose, damaged or corroded connections may contribute to a fault code on a circuit when the sensor or component is operating properly. Be sure that the components are faulty before replacing them, especially the expensive ones.

Fig. Fig. 1: ALDL/DLC terminal identification for 1987-97 vehicles, except 1997 models with a 16-pin DLC
The Assembly Line Diagnostic Link (ALDL) or Data Link Connector (DLC) may be located under the dashboard, and is sometimes covered with a plastic cover labeled DIAGNOSTIC CONNECTOR.

1. The diagnostic trouble codes can be read by grounding test terminal B . The terminal is most easily grounded by connecting it to terminal A (internal ECM ground). This is the terminal to the right of terminal B on the top row of the ALDL connector.
2. Once the terminals have been connected, the ignition switch must be moved to the ON position with the engine not running.
3. The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition switch OFF and remove the jumper wire. Turn the ignition ON and confirm that the light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
4. The code(s) stored in memory may be read through counting the flashes of the dashboard warning lamp. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
5. After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.

The order of codes in the memory does not indicate the order of occurrence.

1. If there are no codes stored, but a driveability or emissions problem is evident, the system should be diagnosed by an experienced driveability technician.
2. If one or more codes are stored, record them. Refer to the applicable Diagnostic Code chart in this section.
3. Switch the ignition OFF when finished with code retrieval or scan tool readings.

After making repairs, clear the trouble codes and operate the vehicle to see if it will reset, indicating further problems.

Fig. Fig. 2: Engine diagnostic trouble codes - 1987-93 vehicles, and 1994 vehicles with a 12-pin DLC connector

197 VEHICLES WITH 16-PIN DLC AND ALL 1995-99 MODELS

See Figures 3 through 7

Fig. Fig. 3: DLC terminal identification for 1994 vehicles with a 16-pin DLC, as well as all 1995-99 models
On 1994-95 3.4L and 3.8L engines, and all 1996 models, an OBD-II compliant scan tool must be used to retrieve the trouble codes. Follow the scan tool manufacturer's instructions on how to connect the scan tool to the vehicle and how to retrieve the codes.

Fig. Fig. 4: Engine diagnostic trouble codes (1 of 4) - 1994 vehicles with a 16-pin DLC and all 1995-99 vehicles

Fig. Fig. 5: Engine diagnostic trouble codes (2 of 4) - 1994 vehicles with a 16-pin DLC and all 1995-99 vehicles

Fig. Fig. 6: Engine diagnostic trouble codes (3 of 4) - 1994 vehicles with a 16-pin DLC and all 1995-99 vehicles

Fig. Fig. 7: Engine diagnostic trouble codes (4 of 4) - 1994 vehicles with a 16-pin DLC and all 1995-99 vehicles

Hi, your 94 model is not OBD2 compliant. You would need an OBD1 scanner to pull the codes. The connector should be under the dash. There is a manual code extraction procedure I have pasted below. Please let me know if you have more questions, and thanks for using FixYa.

On 1983-94 models, the ALDL connector or Data Link Connector (DLC), located under the dash, and sometimes covered with a plastic cover labeled DIAGNOSTIC CONNECTOR, can be activated by grounding test terminal B . The terminal is most easily grounded by connecting it to terminal A (internal ECM ground), the terminal to the right of terminal B on the top row of the ALDL connector. Once terminals A and B have been connected, the ignition switch must be moved to the ON position with the engine not running.

1. Turn the ignition switch OFF .
2. The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition OFF and remove the jumper wire. Turn the ignition ON and confirm that light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
3. The code(s) stored in memory may be read either through counting the flashes of the dashboard warning lamp or through the use of a hand-held scan tool. If using the scan tool, connect it correctly to the ALDL.
4. After the terminals are connected, turn the ignition switch to the ON position, but DO NOT start the engine. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
5. After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.

The order of codes in the memory does not indicate the order of occurrence.

1. If there are no codes stored, but a driveability or emissions problem is evident, the system should be diagnosed by an experienced driveability technician.
2. If one or more codes are stored, record them. Refer to the applicable Diagnostic Code chart in this section.
3. Switch the ignition OFF when finished with code retrieval or scan tool readings.

ok, there are 16 pins in the DLC you want to jump #4 and #12 as you look at the connector from left to right top row is 1-8 bottom row from left to right 9-16, both rows the 4th pin jump them together. then count the flashes all codes are 2 diget ( example flash-flash pause flash-flash = code 22 )

Locate your aldl connector under dash near steering column. It should have 12 pin connector. Older cars had 8 pin connector. You can do either one. On 12 pin connector jump the last 2 pins, on top row, in connector with paperclip or wire. Turn on ignition till check engine light turns on. Count & write down how many times it flashes. It will flash for example 3 times stop then 1 time = 31 code. In older 8 pin connector jump the 2nd & 4th pins on top.

The jumper set should be the upper top right 2 pins. Sometimes the outside of the pin can be broken, however if you place your jumper ( I've even just used a paper clip) inside both terminals, it should give you a response. Make sure your jumper is placed firmly inside of both terminals, then turn your key.

I believe you have one of those split years which is actually an obdii

You shouldn't need to jumper anything; there is a standardized connector for code readers and it is generally on the driver's side under the dash. Please don't try jumping anything in that connector, you may damage the ECU if you connect the wrong two pins.

Call any of the chain auto parts stores and ask if they will retrieve the codes for you. This is widely available and is done at no charge.