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 MANUALSMAZDA1991929 BASEREPAIR AND DIAGNOSISQUICK LOOKUPSTECHNICAL BULLETINSTECHNICAL SERVICE BULLETINSTRANSMISSION CONTROL SYSTEMSPROPER EC-AT TESTER CONNECTION PROCEDURES (CAT. ST, NO. 002/90)

1991 Mazda 929 Base

Proper EC-At Tester Connection Procedures (CAT. ST, NO. 002/90)

1991 Mazda 929 BaseSECTION Proper EC-At Tester Connection Procedures (CAT. ST, NO. 002/90)

Publication date: 1990-08-01
Reference number: CAT. ST, NO. 002/90

PROPER EC-AT TESTER CONNECTION PROCEDURES

TECHNICAL SERVICE BULLETIN

Reference Number(s): CAT. ST, NO. 002/90, Date of Issue: 8/1/90

P ROPER EC-AT CONNECTION

Models All Models with EC-AT

Bulletin No. 002/90

Category ST

Date 8/1/90

DESCRIPTION

When using the EC-AT Tester, it is critical that the pin connector (with ground) that is located on the bottom left-hand corner of the EC-AT Tester body is never connected at the same time an adapter harness is being used.

Symptom codes should be retrieved from the Control Unit first using the 6-pin connector; after disconnecting the 6-pin connector, the adapter harness can be used for further diagnosis.

"Control Unit" refers to EC-AT Control Unit, except for 1990 626/MX-6 non-Turbo. For these models, the EC-AT Control Unit is incorporated into the Engine Control Unit.

REPAIR PROCEDURE

Please affix the attached label on the left side of the EC-AT Tester body, to the left of the adapter harness connector. On versions with the adapter, affix the label on the top panel of the adapter.

Fig 1: Location to Apply Label

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.