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Article Title: Trouble Code 49 Diagnosis
Contributed By: latechsho

Service Code 49 indicates the spark timing has defaulted to 10 degrees before tap dead center. The SPOUT signal has a variable duty cycle with amplitude that varies from 0.4 volts to VBAT or ~12V. In the event of a SPOUT failure, the DIS module will generate a fixed dwell and constand spark angle based on CID and PIP signals (FMEM mode)

Possible causes:
-- Faulty DIS module
-- Faulty SPOUT circuit

Do this....

Key off, wait 10 seconds.
Disconnect processor 60 pin connector. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service if necessary.
With processor disconnected, disconnect DIS module (pins 1-6)
Using a voltmeter measure the resistance between Test Pin 36 at the ECU connector and the SPOUT circuit at the DIS module Vehicle harness connector.

If resistance is more than 5ohms then you need to look for either a bad wire, or a bad connection at the in-line SPOUT connector. Clean up any corrosion at DIS module as well as SPOUT connector. Reconnect it all, and rerun the test.

If resistance is LESS than 5ohms Measure the resistance between ECU harness pin 36 and pins 16&40, also measure resistance between pin 36 and the positive battery post.

If all resistances are greater than 10,000 ohms than the EEC system checks out ok. Reconnect all components and test the DIS.

If all resistances are less than 10,000 ohms than there is a short circuit in the SPOUT circuit to either the power or ground.

ECU Pinout Diagram

note: Take special care not to damage the pins while testing. The official instruction call to use a breakout box for this procedure for that very purpose.

DIS Pinout Diagram

PIN 1 VBAT (BATTERY VOLTAGE)
PIN 2 CID
PIN 3 PIP OUT
PIN 4 PIP IN
PIN 5 SPOUT
PIN 6 DPI (DUAL PLUG INHIBIT)

PIN 7 IGN (MODULE GROUND)
PIN 8 COIL 3
PIN 9 COIL 4
PIN 10 COIL 2
PIN 11 COIL 1
PIN 12 IDM (IGNITION DIAGNOSTIC MODULE)