VIN Decoding

Digit

1. Country

2. Manufacturer

G - General Motors

3. Division

1 - Chevrolet

4. Car line code

5. Series

6+7. Body Style

8. Engine

9. Check Digit

IGNORE

10. Year

11. Production Plant

12-17 Sequential Build

 

RPO Decoding

Regular Production Option Codes
for
1985-1987 GM Products

You can find your Service Parts Identification tag on the inside of the trunk lid.
(Example below.) 

Service Parts Identification  	          DO NOT REMOVE


1G1GZ11G0HP146030

AR9 B4V C1R D35 E5Z J41 MX0 N90 T1S US6 V73 I2U 82D
A01 B72 C18 D55 FFL K64 NA5 P0N T93 U16 YT9 6NY 82I
BV8 B77 C49 D71 F41 L69 NK3 P20 UM6 U39 Z65 7NY BX5
B89 C60 D80 GT4 G80 MW9 N33 QYH VP8 V64 1A4 8HK 9HK
829 B29 CD4


                   U.WA8535




PRINTED IN USA           07MR87       PART NO. 14085266

Z65, BV4, F41, L69 must appear on all true 83-88 SS's

RPO Code Definitions

The following listing is most of the GM Production Options. These options are also known as the RPO codes.
To find out what options your car was ordered with you may look up all the codes listed on your Service Parts Identification tag.

GM Regular Production Options by Family

AIR CONDITIONING AND HEATER C36-C69
AXLE, FRONT (RELATED) FL1-FX2, F16-F82
AXLE, REAR (RELATED) HO1-H99, HA1-HY9, GO1-G99, GA1-GY9
BRAKES JS0-J99, JA1-JY9
BUMPER COMPONENTS V30-V99, VN1-VY9
DEFOGGER - REAR GLASS C47-C50
ELECTRICAL, CHASSIS UO1-U99, T60-T99
ENGINE (RELATED) KO1-K99, KA1-KY9, LO1-L99, LA1-LY9
EXTERIOR ORNAMENTATION BVZ-BY1, B51-B99
FUEL, EXHAUST AND EMISSIONS NO1-N29, NA1-NN9
GLASS AO1-A33, AA1-AA9
INTERIOR ORNAMENTATION BB8-BV9, B18-B48
LAMPS C71-C97
LOCKS AU3-AU6
MIRRORS, BODY DD4-DK5, D28-D78
MOULDINGS AND EXT EMBLEMS B71-B94
RADIATOR AND GRILL VO1-V29, VA1-VM9
RADIO RELATED UK1-UY8, U56-U96
ROOF, ORNAMENTATION AND TRIM CA1-CC3, C01-C10
SEATS, SEAT ADJUSTERS A34-A81, AE5-AV7
SPRINGS 6AA-6ZZ, 7AA-7ZZ, 8AA-8ZZ, 9AA-9ZZ
STEERING (RELATED) N30-N59, NN1-NY9
STRIPES, BODY DECOR DX1-DY6, D84-D99
SUSPENSION F40-F99, FN1-FY9
TRANSMISSION M01-M99, MA1-MY9
WHEEL AND TIRE N60-N99, P01-P99, PA1-PH9, PW1-PY9, R01-R30
WIPER/WASHER/WINDSHIELD CD2-CE4, C18-C25
ECM codes
Submitted by: Joseph J Sigmon (Joseph.J.Sigmon@lerc.nasa.gov)
Trouble codes  Circuit or system  Probable cause
Code 12 

(1 flash, pause, 2 flashes)

 No distributor reference pulses to ECM This code will flash whenever the diagnostic terminal is grounded with the ignition turned On and the engine not running. If additional trouble codes are stored in the ECM they will appear after this code has flashed three times. If this code appears while the engine is running, no reference pulses from the distributor are reaching the ECM.
Code 13 

(1 flash, pause, 3 flashes)

 Oxygen sensor circuit Check for a sticking or misadjusted throttle position sensor. Check the wiring and connectors from the oxygen sensor. Replace the oxygen sensor.
Code 14 

(1 flash, pause, 4 flashes)

 Coolant sensor/high temp If the engine is experiencing overheating problems the problem must be rectified before continuing. Check all wiring and connectors associated with the coolant temperature sensor. Replace the coolant temperature sensor.
Code 15 

(1 flash, pause, 5 flashes)

 Coolant sensor/low temp See above, then check the wiring connections at the ECM.
Code 21 

(2 flashes, pause, 1 flash)

 Throttle position sensor/voltage high Check for a sticking or misadjusted TPS plunger. Check all wiring and connections between the TPS and the ECM. Adjust or replace the TPS
Code 22 

(2 flashes, pause, 2 flashes)

 Throttle position sensor/voltage low Check the TPS adjustment. Check the ECM connector. Replace the TPS
Code 23 (carbureted) 

(2 flashes, pause, 3 flashes)

 Mixture control solenoid The mixture control solenoid is open or grounded.
Code 24 

(2 flashes, pause, 4 flashes)

 Vehicle speed sensor A fault in this circuit should be indicated only when the vehicle is in motion. Disregard Code 24 if it is set when the drive wheels are not turning. Check the connections at the ECM. Check the TPS setting.
Code 32 (carbureted) 

(3 flashes, pause, 2 flashes)

 BARO circuit low Barometric pressure sensor circuit low.
Code 32 (fuel injected) 

(3 flashes, pause, 2 flashes)

 EGR Vacuum switch shorted to ground on start-up, switch not closed after the ECM has commanded the EGR for a specified period of time or the EGR solenoid circuit is open for specified period of time. Replace the EGR valve.
Code 33 

(3 flashes, pause, 3 flashes)

 MAP sensor Check the vacuum hoses from the MAP sensor. Check the electrical connections at the ECM. Replace the MAP sensor
Code 34 

(3 flashes, pause, 4 flashes)

 Vacuum sensor or MAP sensor Code 34 will set when the signal voltage from the MAP sensor is too low. Instead the ECM will substitute a fixed MAP value and use the TPS to control fuel delivery. Replace the MAP sensor.
Code 35 (carbureted) 

(3 flashes. pause, 5 flashes)

 ISC valve Idle Speed Control error. Replace the ISC.
Code 41 

(4 flashes, pause, 1 flash)

 EST circuit No distributor reference pulses to the ECM at specified engine vacuum
Code 42 

(4 flashes, pause, 2 flashes)

 Electronic Spark Timing Electronic Spark Timing bypass circuit or EST circuit is grounded or open. A malfunctioning HEI module can cause this code.
Code 43 

(4 flashes, pause, 3 flashes)

 Electronic spark control unit The ESC retard signal has been on for too long or the system has failed a functional check
Code 44 

(4 flashes, pause, 4 flashes)

 Lean exhaust Check the ECM wiring connections, particularly terminals 15 and B. Check for vacuum leakage at the TBI base gasket, vacuum hoses or the intake manifold gasket. Replace the oxygen sensor
Code 45 

(4 flashes, pause, 5 flashes)

 Rich exhaust Check the evaporative charcoal canister and its components for the presence of fuel. Replace the oxygen sensor.
Code 51 

(5 flashes, pause, 1 flash)

 PROM or MEM-CAL Make sure that the PROM or MEM-CAL is properly installed in the ECM. Replace the PROM or MEM-CAL
Code 52 

(5 flashes, pause, 2 flashes)

 CALPAK Check the CALPAK to insure proper installation. Replace the CALPAK
Code 53 (carbureted) 

(5 flashes, pause, 3 flashes)

 EGR valve Exhaust Gas Recirculation valve vacuum sensor has received improper EGR vacuum.
Code 54 (carbureted) 

(5 flashes, pause, 4 flashes)

 M/C solenoid The mixture control solenoid voltage is high at the ECM because of a shorted M/C solenoid circuit and/or faulty ECM.
Code 54 (fuel injected) 

(5 flashes, pause, 4 flashes)

 Fuel pump Low fuel pump voltage. Sets when the fuel pump voltage is less than 2 volts when reference pules are being received.
Code 55 

(5 flashes, pause, 5 flashes)

 ECM Be sure that the ECM ground connections are tight. If they are replace the ECM.
 

NOTE: The information contained herein, is to the best of my knowledge accurate. If you find any errors please E-Mail me and I will make the necessary corrections.

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