Does it work?

I googled GM '94 diagnostic paper clip, and I'm findin' pages that say '94 and newer can't be done with a paper clip.

True?

If not, link to procedure?

Thanks

 

Pre '96 Corvettes will reveal codes when the proper terminals in the diagnostic connector are 'shorted' or connected.
'95 for sure and perhaps '94 (I've never had a chance to look at one) Corvettes had OBD I diagnostics but with an OBD II connectors. For that OBD II connector on an OBD I diagnostics car, connect the #4 and #12 terminals to display codes. Terminals are numbered from top left to right, then second row from left to right. #4 is above #12. I don't know the number layout for OBD I connectors.
If you have a service manual, it explains how to read the codes using the buttons in the 'Drivers Information Center' (the Trip/Odometer, Gauges, Fuel, etc. buttons). No need for a paper clip or expensive diagnostic code reader.
More expensive code readers will read both OBD I and II connectors and systems. The less expensive ones (about $100) typically read only OBD II diagnostics. But that's OK since the OBD I systems can be read with a paper clip.
Most importantly, do a search for OBD I and II diagnostics and connectors using the 'search' tab above. There's a wealth of information.

 

Thanks IRA...

I pulled up:

1. H41
4. H13, H63
9. ---
A.
1.0

I'm searchin' now...

 

Several months ago I copied this from a post;
Hope it's accurate. And H means history, not doing it now.
Sorry, my text editor lost the columns.

1994-1996: Diagnostic Trouble Codes
DTC #11: Malfunction Indicator Lamp Circuit.DTC #13: Bank #1 Heated Oxygen Sensor #1 Circuit: DTC #14: Engine Coolant Temperature Sensor Circuit Voltage Low.DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High.DTC #16: Distributor Ignition System Low Pulse.DTC #18: Injector Circuit.DTC #21: Throttle Position Sensor Circuit Voltage High.DTC #22: Throttle Position Sensor Circuit Voltage Low.DTC #23: Intake Temperature Sensor Circuit Voltage High.DTC #24: Vehicle Speed Sensor Circuit.DTC #25: Intake Air Temperature Sensor Circuit Voltage Low.DTC #26: Evaporative Emission Canister Purge Solenoid Valve Circuit.DTC #27: EGR Vacuum Control Signal Solenoid Valve Circuit.DTC #28: Transmission Range Pressure Switch Assembly Fault.DTC #29: Secondary Air Injection Pump Circuit.DTC #32: Exhaust Gas Recalculation.DTC #33: Manifold Absolute Pressure Sensor Circuit High.DTC #34: Manifold Absolute Pressure Sensor Circuit Low.DTC #36: Distributor Ignition System High Pulse.DTC #37: Brake Switch Stuck On.DTC #38: Brake Switch Stuck Off.DTC #41: Ignition Control Circuit Open.DTC #42: Ignition Control Circuit Shorted.DTC #43: Knock Sensor Circuit.DTC #44: Bank 1 LF Heated Oxygen Sensor #1 Circuit Lean.DTC #45: Bank 1 LF Heated Oxygen Sensor #1 Circuit Rich.DTC #47: Knock Sensor Circuit Or Module Missing.DTC #48: Mass Air Flow Sensor Circuit.DTC #50: System Voltage Low.DTC #51: EPROM Programming Error.DTC #52: Engine Oil Temperature Sensor Circuit Voltage Low.DTC #53: System Voltage Low.DTC #55: Fuel Lean Monitor.DTC #58: Transmission Fluid Temperature Sensor Circuit Low.DTC #59: Transmission Fluid Temperature Sensor Circuit High.DTC #62: Engine Oil Temperature Sensor Circuit Voltage Low.DTC #63: Bank 2 RF Heated Oxygen Sensor #1 Circuit Open.DTC #64: Bank 2 RF Heated Oxygen Sensor #1 Circuit Lean.DTC #65: Bank 2 RF Heated Oxygen Sensor #1 Circuit Rich.DTC #66: A/C Refrigerant Pressure Sensor Circuit Open.DTC #67: A/C Pressure Sensor Circuit Sensor or A/C Clutch.DTC #68: A/C Relay Circuit.DTC #69: A /C Clutch Circuit.DTC #70: A/C Clutch Relay Driver Circuit.DTC #72: Vehicle Speed Sensor Loss.DTC #73: Pressure Control Solenoid Circuit Current Error.DTC #74: Traction Control System Circuit Low.DTC #75: Transmission System Voltage LowDTC #77: Primary Cooling Fan Relay Control Circuit.DTC #78: Secondary Cooling Fan Relay Control Circuit.DTC #79: Transmission Fluid Overtemp.DTC #80: Transmission Component Slipping.DTC #81: Transmission 2-3 Shift Solenoid Circuit.DTC #82: Transmission 1-2 Shift Solenoid Circuit.DTC #83: Torque Converter Solenoid Voltage High.DTC #84: 3-2 Control Solenoid Circuit.(Auto Only).DTC #84: 2nd And 3rd Gear Blockout Relay Control Circuit. DTC #85: Transmission TCC Stock On.DTC #90: Transmission TCC Solenoid Circuit.DTC #91: One To Four Upshift Lamp(Manual Only).DTC #97: VSS Output Circuit.DTC #98: Tachometer Output Signal Voltage Wrong.

 

See link below.

http://www.corvettephotographs.com/c4vettes/codes.htm

 

bookmarked!




Both circuits didn't fail at the same time, did they?

Only thing in common is the computer (code 41)???

 

Is this a '94 FSM? Can anybody tell?

I'm askin' cause I got the codes by linking pins 4 and 12. The diagnostic chart above says start by linking pins 'A' and 'G'.

HUH?

 

I have a nice scanner that reads the 94-95 corvette scan dilemma.

my local autoparts store could not read it, OBD2 only. I can drive down the road and read real time data along with everything the computer sees. everything from desired idle RPM to O2 sensor readings.

this is way better than ANY paper clip scan can do. real time data with all trouble codes.

and you say your 45 minutes from anywhere, if you want to come here and use it, your more than welcome. I just may put you to work changing plug wires on my 95 is all.

 

Yeah - thanks boost!

Now I just need diagnostic sequence for both sides heated O2 failure (probably NOT the problem), and Ignition Control Circuit Open (MOST likely the problem). 'H' codes too - intermittent, they just started this morning.

Help?

 

What kind of scanner do you use Overboost? I have a 94 and I am looking to pick up a scanner to deal with any future problems.

 

A to B is usually used with a 12 pin dlc.

This site will explain the procedure.

http://www.corvettephotographs.com/c4vettes/index.htm

 

it is an auto Xray 6000

works great and has saved my butt from trouble more than once.

It can read anything from 82 up any year, any make.

you just have to know how to "do it"
took me a week to figure out how to get it to scan this 95

 

Thanks for the scanner info Overboost

 

Some pretty good stuff Dwarf.

So I checked the wiring; it's still there.

Not sure I should buy an ignition module yet; I think other things would be broken if the Ig Mod was toast.

????????????????????????????????????

Anybody else?

 

Do the heated O2 sensors ground at the sensor? Or do they return to a common ground (for both of them?).

Either way, it's still an intermittent problem - 'H' code, as is the 41 Ig control circuit intermittent.

Anybody?

 

they run into the harness and all 4 should connect together into a common ground.

 

That's what I have. Well worth the money.

Phil

 

Can you post up the wiring diagram for a '94 or close to that year model?

All three popped up at the same time - there's no reason for me to troubleshoot till I find the common link.

A trip to the dealer would just be foolish for 3 problems and one cause.

 

I have book 1, I think the diagrams are in book 2.

I have been meaning to buy book 2....

 

Ebay has 3 sellers with book 2 only.

???

I want either the whole set, or the preliminary book. No reason to buy #2, when something I need might be in #1...