DTC P1776 & DTC P1777: IGN RETARD REQUEST DURATION OR CKT
NOTE: After each repair, clear DTCs. See CLEARING CODES/PCM RESET PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Turn ignition off and then on. Read DTCs to verify repair is complete. For DLC and PCM connector terminal identification, see CONNECTOR IDENTIFICATION. For wiring diagrams, see WIRING DIAGRAMS.
Using scan tool, read DTCs. If DTC P1776 or P1777 is present, start engine and run at idle. Wait 20 seconds to check if Transmission Control Module (TCM) is in substitute function (sport mode cannot be engaged). If TCM is in substitute function, go to next step. If TCM is not in substitute function, go to step 4.
Ensure PCM and TCM harness and connectors are not damaged and connections are okay. Repair as necessary. If harness and connectors are okay, using DVOM, check for continuity of Gray/Blue wire between PCM Red connector terminal No. 26 and TCM connector terminal No. 32. Repair wiring as necessary. If wiring is okay, go to next step.
Use oscilloscope to check pulse width modulated signal. If signal is less than 10 percent or more than 19 percent, TCM is faulty. Replace TCM. If signal is as specified, go to next step.
Inspect for PCM DTCs. If PCM DTCs are present, replace PCM. If PCM DTCs are not present, clear DTCs. Turn ignition off and then on. Read DTCs. If DTC P1776 or DTC P1777 is not present, repair is complete. If DTC P1776 or P1777 is present, replace PCM.