MIL ON, AIR Fuse Blows, DTC 29, or 410 Set
File In Section: 6E - Engine Fuel & EmissionBulletin No.: 63-65-02
Date: March, 1996
Subject:
Malfunction Indicator Lamp (MIL) may be On, DTC 29 or 410 Set, AIR Fuse Blows (Increase Wire and Fuse Size)
Models:
1993-96 Chevrolet Camaro
1993-96 Pontiac Firebird
with 5.7L Engine Only (VIN P - RPO LT1)
Condition
Some owners may comment that the Malfunction Indicator Lamp (MIL) may be on. Diagnostic Trouble Code (DTC) 29 (on 1993-95 models) or 410 (on 1996 models) is set. The AIR fuse (# 7) in the underhood electrical center will be blown.
Cause
The AIR pump fuse and wiring are not adequate to prevent the fuse from blowing under some conditions. The AIR pump operates only on a cold start up, before the engine goes into closed-loop operation.
Correction
A 25 amp fuse, and wiring increased from 0.8 mm (18 gauge) to 1.0 mm (16 gauge), went into production approximately 11-29-95.
Normally, the AIR pump will not be damaged and will not have to be replaced. To verify that the AIR pump is still operational, replace the fuse, then use the TECH 1 to operate the pump following the directions in DTC 29 chart in the Service Manual. The pump should run and deliver air to the engine ports. Listen for any unusual noises that could indicate bearing problems. If any indication of water is found, replace the pump. The steady state current draw of the pump should be no more than 15 amps. If the pump operates normally, it will not have to be replaced.
1993-95 Vehicles
Use the following procedure to change the AIR pump fuse to 25 amps, increase the wire size from the AIR pump relay to the AIR pump, and update the label on the cover of the underhood electrical center. The wiring diagram for this circuit is on Page 8A-21-3 of the 1995 Service Manual.
1. Disconnect the negative battery cable.
2. Remove the air cleaner/mass air flow (MAF) sensor assembly.
3. a. Remove the underhood electrical center to gain access to the wiring on the bottom.
b. Remove the AIR pump relay.
c. Remove terminal E4 (two red wires attached). Cut the old terminal off.
d. Crimp a 36 inch (900 mm) length of new 1.0 mm (16 gauge) red wire, and the existing 1.0 mm red wire, to new terminal, P/N 12015870. Solder the connection.
Important: Some vehicles may have been built with both red wires of the same gage. In this case, use an ohmmeter to determine which wire to reconnect. Connect one lead of the ohmmeter to terminal "A" at the AIR pump connector. Touch the other lead to each of the two red wires. The one that has very low resistance (close to "0") is the wire that will NOT be used. This is the wire that goes to terminal "A". Cut it off and tape it.
e. Insert the terminal into the electrical center. Reinstall the AIR pump relay.
f. Route the new wire to the AIR pump using the old wire as a guide. Secure the wire as needed to prevent cutting or rubbing.
4. a. Remove the connector from the AIR pump.
b. Remove terminal "A" from the connector; cut off and discard the old terminal. Carefully remove the old seal from the terminal and reuse it.
c. Cut off any excess length of new wire. Crimp and solder a new terminal, P/N 12048074, to the new 1.0 mm wire. Reuse the seal from above.
d. Install the terminal into the connector, then reattach the connector to the AIR pump.
5. a. Reinstall the underhood electrical center, then connect the negative battery cable. Reinstall the air cleaner/MAF sensor assembly.
b. Install a 25 amp fuse in the AIR pump (# 7) location.
c. Clean the present label on the inside cover of the underhood electrical center, then cut out just the "25 amp" part of label, P/N 12191559, and apply it over the existing label.
d. Verify that the AIR pump operates.
1996 Models
Use the following procedure to change the AIR pump fuse to 25 amps, increase the wire size from the A/P-Fan Fuse to the AIR pump relay, and add a new label to the cover of the underhood electrical center. The wiring diagram for this circuit is on page 8A-21-3 of the 1996 Service Manual.
Important: The wiring diagram shows the wire from S189 to terminal "A" on the AIR pump as 0.8 mm. However, it is actually 1.0 mm and will not have to be replaced.
1. Disconnect negative battery cable.
2. a. Remove the underhood electrical center to gain access to the wiring on the bottom.
b. Remove the AIR pump relay and the A/P-Fan fuse (# 7).
c. Remove terminal E1 (0.8 mm orange) from the relay location. Cut the old terminal off, and tape the wire. This wire will not be used.
d. Remove terminal L7 (0.8 mm orange) from the fuse location. Cut off and discard the terminal. Crimp and solder a new terminal, P/N 12020321, to a 9 inch (225 mm) length of new 1.0 mm orange wire AND the existing orange wire from L7.
e. Install the new terminal into cavity L7.
f. Crimp and solder a new terminal, P/N 12015869, to the other end of the new wire.
g. Install this new terminal into cavity E1.
3. a. Reinstall the underhood electrical center.
b. Install a 25 amp fuse in the AIR pump (# 7) location. Reinstall the AIR pump relay.
c. Clean the present label on the inside cover of the underhood electrical center, then apply a new label, P/N 12191559.
d. Reconnect the negative battery cable. Verify that the AIR pump operates.
Parts Information
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Labor Time
N6276 Use published labor operation time.