Tachometer Inoperative On Models With Clean Tach Output (CTO) Only

Check CTO circuit from PCM terminal No. 48. Go to TEST JH, step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. To determine if CTO circuit is used, see appropriate PIN VOLTAGE/PID VALUE CHARTS article. Check terminal No. 48 under OUTPUTS.