TEST B: PASS Key Decoder Module

WARNING: This page is about a different car, the 1990 Cadillac Allante. However, it is still accessible from the selected car via links, so may be relevant.

Measure values at PASS Key decoder module connector. Module connector is disconnected. See PASSKEY DECODER MODULE (TEST 1) table.

PASSKEY DECODER MODULE (TEST 1)

Condition

Measure Between

⁽¹⁾ Correct Voltage

Ignition Switch To RUN

A1 (RED/BLK) & Ground

⁽²⁾ Battery

Ignition Switch To RUN

B8 (RED/YEL) & Ground

⁽³⁾ Battery

Ignition Switch To RUN

B8 (RED/YEL) & B1 (BLK)

⁽⁴⁾ Battery

Ignition Switch To RUN

A2 (BLU) & B1 (BLK)

⁽⁵⁾ 5

Ignition Switch To START

A3 (BLK) & B1 (BLK)

⁽⁶⁾ Battery

⁽¹⁾	If results are correct, measure resistance at PASS Key decoder module connector (disconnected). See PASSKEY DECODER MODULE (TEST 2) table.

⁽²⁾	Check the RED/BLK (439) wire and Fuse 14 for an open.

⁽³⁾	Check the RED/YEL (2) wire and Fuse 4 in Maxi fuse block for an open.

⁽⁴⁾	Check the BLK (1033) wire for an open.

⁽⁵⁾	Check the BLU (229) wires for an open, or a short to battery or ground. If wire is good, see PFI CHART C-1: ECM REPLACEMENT CHECK in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

⁽⁶⁾	Check BLK (625) wire for an open. If wire is good, see TEST C: STARTER ENABLE RELAY .

PASSKEY DECODER MODULE (TEST 2)

Condition

Measure Between

⁽¹⁾ Correct Resistance

No Key In Ignition Switch

A6 (PPL) & Ground

⁽²⁾ Open Circuit

No Key In Ignition Switch

A6 (PPL) & B2 (PPL/WHT)

⁽³⁾ Open Circuit

Key In Ignition Switch

A6 (PPL) & B2 (PPL/WHT)

⁽⁴⁾ In The Range Of 380 To 12.3K Ohms

⁽¹⁾	If resistance is correct but engine will not crank, replace the PASS Key decoder module.

⁽²⁾	Check PPL (1073) wire for a short to ground. The short may be in the steering column.

⁽³⁾	Check PPL (1073) and PPL/WHT (1074) wires for shorts between the two wires. The short may be in the steering column.

⁽⁴⁾	Check PPL (1073) and PPL/WHT (1074) wires for an open.