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.
Pinpoint Test F: No Communication With The Electronic Automatic Temperature Control (EATC) Module
- F1 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN
- Key in OFF position.
- Disconnect: DATC C2356a or EATC Module C228a.
- Measure the resistance between DATC C2356a-1 or EATC module C228a-1, circuit GD116 (BK/VT) and ground.
- Is the resistance less than 5 ohms?
Yes : GO to F2.
No : REPAIR circuit GD116 (BK/VT). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
- F2 CHECK CIRCUITS SBP07 (WH/RD) AND CBP20 (YE/VT) FOR AN OPEN
- Key in ON position.
- Measure the voltage between DATC C2356a-26 or EATC module C228a-26, circuit SBP07 (WH/RD), DATC C2356a-19 or EATC module C228a-19, circuit CBP20 (YE/VT) and ground.
- Is the voltage greater than 10 volts?
Yes : GO to MODULE COMMUNICATIONS NETWORK to diagnose the network concern.
No : VERIFY smart junction box (SJB) fuses 13 (7.5A) and 27 (7.5A) are OK. If OK, REPAIR circuit SBP07 (WH/RD) or CBP20 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.