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Is a 95' OBD 1 or 2

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
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13,453
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CenCoast CA
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71 04 12 19
94 and 95 base cars have partial OBDII capability which was part of GM's so-called "early-rollout of OBDII". The engines in those cars have partial OBDII systems and the ECM's will set some OBDII DTCs but none of them turn on the MIL. Only OBDI codes turn the light on in those cars. A scan tester which supports partial OBDII on OBDI systems can read those codes.

Because of the partial OBDII capability, 94 and 95 base cars do not support flash-code diagnostics nor will they display DTCs on their IPs. The FSM says they will, but they won't.

94 and 95 ZR-1s *do* support flash-code and do not have the partial OBDII capability.

"Full" OBDII began in MY96
 

John Robinson

Gone but not forgotten
Joined
May 3, 2005
Messages
1,555
Location
Muncie, Indiana
Corvette
1993 Polo Green Coupe
I believe the OBDII was introduced in the 94 model year. The ECM should have cooling fins on it. The cars equiped with the OBDI had the 4L60 Automatic transmission which was cable operated for the shift points. When they went to the 4L60E (The E is for electric shift) transmission they had to go to OBDII because the shifting of the transmission was controlled by the ECM electrically.:v
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,453
Location
CenCoast CA
Corvette
71 04 12 19
I believe the OBDII was introduced in the 94 model year. The ECM should have cooling fins on it. The cars equiped with the OBDI had the 4L60 Automatic transmission which was cable operated for the shift points. When they went to the 4L60E (The E is for electric shift) transmission they had to go to OBDII because the shifting of the transmission was controlled by the ECM electrically.:v

Though it is true that the 4L60-E was introduced for 94, its introduction is strictly coincidence. The type of transmission used for 94 has no direct bearing on the existence of OBDII. The two are, however, indirectly related because GM had to redesign the engine controller for OBDII and took that opportunity to add the trans controls.

OBDII was mandated by Federal law starting in MY96 and GM wanted some field experience with the system before it put OBDII on all it's vehicles. Corvette and a couple of other GM platforms had partial OBDII in MY94 and 95.
 

OldCorvetteFan

Well-known member
Joined
Jul 3, 2005
Messages
117
Location
Northwest Illinois
Corvette
Black 95 6 spd Coupe (Sold); 2011 GS
94 and 95 base cars have partial OBDII capability which was part of GM's so-called "early-rollout of OBDII". The engines in those cars have partial OBDII systems and the ECM's will set some OBDII DTCs but none of them turn on the MIL. Only OBDI codes turn the light on in those cars. A scan tester which supports partial OBDII on OBDI systems can read those codes.

Because of the partial OBDII capability, 94 and 95 base cars do not support flash-code diagnostics nor will they display DTCs on their IPs. The FSM says they will, but they won't.

Are you talking about the DTC's set by the CCM? Those are accessible following the FSM instructions.

Steven
 

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