89 Vert 6speed with Error Codes 23 and 34
Thread Starter
Racer
Joined: Mar 2001
Posts: 280
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From: Honolulu Hawaii
89 Vert 6speed with Error Codes 23 and 34
Hi, I have an 89 Convertible 6speed with Error codes 23 and 34. Anyone have any advice on these 2 codes? I looked up the codes and Code 23 is Manifold Air Temperature Circuit High. Would this be changing the Intake Air Temp Sensor? Code 34 says Mass Air Flow Sensor Low. Does that mean a bad MAF sensor?
When I start my vette cold, it takes a couple cranks before it starts and sometimes I have to rev it up a minute or two to warm it up before it runs ok. When cold, it dies if I don't rev it.
Thanks for any input
-Tim
When I start my vette cold, it takes a couple cranks before it starts and sometimes I have to rev it up a minute or two to warm it up before it runs ok. When cold, it dies if I don't rev it.
Thanks for any input
-Tim
Team Owner
Joined: Sep 2001
Posts: 62,162
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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You always start with the code that comes up first in the airflow, so fix the 34 first, clear all codes and see if 23 comes back, then fix that one.
If you only have to replace the relays behind the battery, replace both. If you have to replace the MAF sensor, replace both relays at the same time.
If you only have to replace the relays behind the battery, replace both. If you have to replace the MAF sensor, replace both relays at the same time.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
There could be a problem in the MAF wiring. Also you might have dirty contacts in the MAF connector.
The same advice applies to the MAT sensor. My recollection is that the default is a high if the MAT is disconnected (which also could be a bad connection or broken wire). Check the MAF power (12 volts) on pin E of the connector.
This diagram is for my '86 but I don't think it changed for '89:
Based on the diagram, it appears the fuel pump must be running to power the MAF. That doesn't seem right...
.
The same advice applies to the MAT sensor. My recollection is that the default is a high if the MAT is disconnected (which also could be a bad connection or broken wire). Check the MAF power (12 volts) on pin E of the connector.
This diagram is for my '86 but I don't think it changed for '89:
Based on the diagram, it appears the fuel pump must be running to power the MAF. That doesn't seem right...
.
Last edited by Cliff Harris; Jan 6, 2016 at 01:18 AM.
Thread Starter
Racer
Joined: Mar 2001
Posts: 280
Likes: 0
From: Honolulu Hawaii
UPDATE: Unplugging and reconnecting the MAF sensor connector seems to have cleared the Code 34. Changing out the MAT Sensor cleared the Code 23. No more SES light. Thanks for everyone's help.
-Tim
-Tim
Team Owner
Joined: Sep 2001
Posts: 62,162
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
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