I bought a 1998 mitsubishi eclipse and the check engine light came on we hooked up the machine to diagnos it and we got 2 codes po700 and p1784 . we are wondering what the codes mean and how to fix the problem.

DTC 1784: LOW-REVERSE PRESSURE SWITCH
1.Remove transaxle relay from connector. Turn ignition on. Install scan tool and observe low-reverse pressure switch condition. Apply battery voltage to transaxle relay connector terminal No. 8. If low-reverse pressure switch stays off, go to next step. If low-reverse pressure switch turns on, go to step 4 .

2.Raise vehicle enough to allow drive wheels to spin freely. Test low-reverse clutch hydraulic pressure. See HYDRAULIC PRESSURE TESTS under TESTING. If low-reverse clutch pressure test is not within specification, internal transaxle failure exists. If low-reverse clutch pressure test is within specification, observe scan tool.

3.If low-reverse pressure switch turns on, trouble code is intermittent. Check wire harnesses and connectors for damage or poor connection. If low-reverse pressure switch does not turn on, replace solenoid and pressure switch assembly. Recheck trouble codes. If trouble code resets, replace TCM.

4.Check and repair wiring harness between transaxle relay connector and solenoid and pressure switch assembly connector. If wiring harness is okay, check wire between TCM connector terminal No. 10 and solenoid and pressure switch assembly.

5.If wire between TCM connector terminal No. 10 and solenoid and pressure switch assembly is okay, check TCM and solenoid and pressure switch assembly connectors. Repair connectors as necessary. If connectors are okay, recheck trouble codes. If trouble code resets, replace solenoid and pressure switch assembly. Recheck trouble codes. If trouble code resets, replace TCM.

P0700-The Transmission Control Module (TCM) monitors the malfunction of sensors and actuators relating to transmission control. When the TCM detects a malfunction with the control, a signal is send to the Engine Control Module (ECM) to trigger the Engine Light or Service Engine Soon light. The ECM stores the P0700 code and it means the TCM detected a malfunction with the transmission controls.

I would try disconnecting he battery and letting it sit for 5 minutes, then hook it back up to see if they return-the 700 code is probably related to the 1784 code, that seems to be your main issue.

This is the Diagnostic Trouble Code Table ,mainly help you to check the trouble code when you diagnose your car with OBDII diagnostic tools.Hope it help.