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 MANUALSPONTIAC1990FIREBIRD TRANS AM, 5.0 F, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEDOOR LOCKSANTI-THEFT SYSTEMSYSTEM TESTINGPASS KEY DECODER MODULE TEST 2
1990 Pontiac Firebird Trans Am, 5.0 F, Standard
Pass Key Decoder Module Test 2
1990 Pontiac Firebird Trans Am, 5.0 F, StandardSECTION Pass Key Decoder Module Test 2
NOTE:
The following table verifies resistance at the Pass Key Decoder Module connector with the connector disconnected, the negative battery cable disconnected and with the key removed from the ignition switch.
PASS KEY DECODER MODULE TEST (TABLE 2A)
| Measure Between | Correct Resistance | For Diagnosis |
|---|---|---|
| A6 (WHT/BLK) & B2 (PPL/YEL) | Open Ckt | See 1 |
NOTE:
The following table continues to verify resistance at the Pass Key Decoder Module connector with the connector disconnected, the negative battery cable disconnected and with the key INSTALLED in the ignition switch.
PASS KEY DECODER MODULE TEST (TABLE 2B)
| Measure Between | Correct Resistance | For Diagnosis |
|---|---|---|
| A6 (WHT/BLK) & B2 (PPL/YEL) | 380 To 12.3K Ohms | See Step 2) |
| * If resistance is correct but engine will not crank, replace PASS Key Decoder Module. | ||
NOTE:
When the Pass Key Decoder Module is replaced, the new key code may not match the code in the owner's existing keys. If it does not match, then new keys must be made. See KEY DUPLICATION PROCEDURE
.
- Check the WHT/BLK (1073) and PPL/YEL (1074) wires for shorts to ground or between the two wires.
- Check the WHT/BLK (1073) and PPL/YEL (1074) wires for an open.
RENDER: 1.0x
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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.