Emissions - Hesitation/Stumble On Accel/Multiple DTC's
98-074March 4, 2010
Applies To:
1990-1993 Accord L4 - ALL
1997-2001 Prelude - ALL
Hesitation or Stumble With Possible DTC(s) P0141, P0171, P0300, P0301, P0302, P0303, P0304, P0401, or P1491
(Supersedes 98-074, dated April 20, 2007, to revise the information marked by the asterisks)
*REVISION SUMMARY
Under REQUIRED SPECIAL TOOLS, the part numbers and ordering information for individual kit items were added.*
SYMPTOM
An engine hesitation or stumble can be felt under light acceleration between 1,500-2,000 rpm. In addition, on 1997-2001 Preludes, one or more of these DTCs may be stored:
^ P0141 (Secondary heated oxygen sensor 2, heater circuit malfunction)
^ P0171 (Fuel system too lean)
^ P0300 (Random misfire detected)
^ P0301 (No.1 cylinder misfire detected)
^ P0302 (No.2 cylinder misfire detected)
^ P0303 (No.3 cylinder misfire detected)
^ P0304 (No.4 cylinder misfire detected)
^ P0401 (Insufficient EGR flow detected)
^ P1491 (Insufficient EGR valve lift detected)
PROBABLE CAUSE
Carbon build-up may be restricting the EGR ports in the intake manifold runners.
CORRECTIVE ACTION
Clean the carbon out of the EGR ports.
PARTS INFORMATION
EGR port plugs (four to six required per vehicle):
P/N 17199-PT3-AHM
REQUIRED SPECIAL TOOLS
EGR Plug Replacement Kit: P/N 07WAZ-001000A (Includes slide hammer, 10-24 threaded screw, No. 25 drill bit, 10-24 tap, and 30 replacement plugs)
This kit is available for purchase through normal parts ordering. It's also available for loan through the Special Tool Loan Program. For details, refer to Service Bulletin 98-051, Special Tool Loan Program.
*For replacement kit items:
Slide Hammer (dent puller type) - OTC P/N 898A
(Call OTC, 507-455-1480, for a local distributor)
10-24 x 3 in. screw - Local purchase
No.25 drill bit (6 in. long) - MSC Industrial P/N DAC581 25-C (Call MSC Industrial, 800-521-9520)
10-24 tap (6 in. long) - MSC Industrial P/N RNE-38342-E (Call MSC Industrial, 800-521-9520)
WARRANTY CLAIM INFORMATION
The normal warranty applies.
Failed Part: P/N 17100-PT3-A00
Defect Code: 06901
Symptom Code: 09202
Skill Level: Repair Technician
DIAGNOSIS
1. Disconnect the vacuum line from the EGR valve, then connect a vacuum pump-gauge to the valve.
2. With the engine idling, apply 10 inches of vacuum.
^ If the engine does not stall, go to step 3.
^ If the engine stalls, this service bulletin does not apply. Continue to troubleshoot for other causes of the hesitation or stumble.
3. Plug the EGR valve's vacuum line, and leave the EGR valve disconnected.
^ If the engine does not stall, go to step 4.
^ If the engine stalls, this service bulletin does not apply. Continue to troubleshoot for other causes of the hesitation or stumble.
4. Test-drive the vehicle.
^ If the hesitation or stumble is gone, go to REPAIR PROCEDURE.
^ If the hesitation or stumble is still there, this service bulletin does not apply. Continue to troubleshoot for other causes of the problem.
REPAIR PROCEDURE
1. If clearance is needed, remove the two mounting bolts for the electronic air control valve (EACV), then move the valve out of the way.
2. Remove the two mounting bolts for the fast idle valve, then move the valve out of the way.
3. Center-punch one of the rear EGR port plugs. Using the No.25 drill bit from the EGR Plug Replacement Kit and a drill, make a hole in the center of the plug. Use a vacuum cleaner to remove the metal shavings as you drill.
4. Using the 10-24 tap from the kit, tap the hole you just drilled. Vacuum out the metal shavings as you tap the hole.
5. Use the 10-24 screw and the slide hammer from the kit to remove the rear EGR port plug from the intake manifold.
6. Using a thick wire (such as a piece of coat hanger), clean out the EGR port hole. Vacuum out as much of the debris as possible.
7. Install a new EGR port plug into the port hole using a brass drift. Make sure the top of the plug is flush with the manifold.
8. Repeat steps 3 thru 7 for the three other rear EGR ports.
NOTE:
If the four rear EGR ports had a lot of carbon in them, repeat steps 3 thru 7 on the two forward EGR ports and their crossover ports.
9. Reinstall the fast idle valve and the EACV using new 0-rings.
10. Clear any stored DTCs.
Disclaimer