Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1986CAPRICE WAGON V8-305 5.0LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTECHNICAL SERVICE BULLETINSALL TECHNICAL SERVICE BULLETINSENGINE CONTROLS - NORMAL PROCEDURES DO NOT FIX CODE 53
1986 Chevrolet Caprice Wagon V8-305 5.0L
Engine Controls - Normal Procedures Do Not Fix Code 53
1986 Chevrolet Caprice Wagon V8-305 5.0LSECTION Engine Controls - Normal Procedures Do Not Fix Code 53
Number: 86-180
Section: 6E
Date: Oct. 1986
Subject: CODE 53 - EGR CONTROL ERROR
MODEL AND YEAR: 1986 CAPRICE WITH 5.0L LG-4 ENGINES (ENGINE CODE H)
TO: ALL CHEVROLET DEALERS
In most cases, normal diagnostic and repair will correct customer complaints of "Service Engine Soon Light" Code 53 (EGR Control Error). If the diagnostics shown in your 1986 Shop Manual (Section 6E1) shows the problem to be no trouble found, it will be necessary to change the PROM in the ECM. Below is a listing of new PROM numbers released to correct this condition.
On Federal Emission (NA-5) Caprice Models
1. Coupes and Sedans Use PROM 1228284
2. Wagons with GU2 (2.73) Axle Use PROM 1228285
3. Wagons with GU4 (3.08) Axle Use PROM 1228286
On California Emission Caprice Models
1. Coupes and Sedans Use PROM 1228287
2. Wagons with GU2 (2.73) Axle Use PROM 1228288
3. Wagons with GU4 (3.08) Axle Use PROM 1228289
Use applicable Labor Time and Operations Numbers.
Section: 6E
Date: Oct. 1986
Subject: CODE 53 - EGR CONTROL ERROR
MODEL AND YEAR: 1986 CAPRICE WITH 5.0L LG-4 ENGINES (ENGINE CODE H)
TO: ALL CHEVROLET DEALERS
In most cases, normal diagnostic and repair will correct customer complaints of "Service Engine Soon Light" Code 53 (EGR Control Error). If the diagnostics shown in your 1986 Shop Manual (Section 6E1) shows the problem to be no trouble found, it will be necessary to change the PROM in the ECM. Below is a listing of new PROM numbers released to correct this condition.
On Federal Emission (NA-5) Caprice Models
1. Coupes and Sedans Use PROM 1228284
2. Wagons with GU2 (2.73) Axle Use PROM 1228285
3. Wagons with GU4 (3.08) Axle Use PROM 1228286
On California Emission Caprice Models
1. Coupes and Sedans Use PROM 1228287
2. Wagons with GU2 (2.73) Axle Use PROM 1228288
3. Wagons with GU4 (3.08) Axle Use PROM 1228289
Use applicable Labor Time and Operations Numbers.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.