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1999 Chrysler Concorde LXI: Diagnosing P1684, P0300, P0700, and P0463 Codes with Transmission in Limp Mode

Model: 99 Chrysler Concorde LXI Fault Code: P0300 Posted: 2015-10-29 05:17

My 1999 Chrysler Concorde LXI is displaying four diagnostic trouble codes: P1684, P0300, P0700, and P0463. The vehicle is currently in limp mode, and the transmission will not shift properly. I've used a key dance method to retrieve these codes, but I'm concerned that this technique may not be as thorough as using a proper OBD2 scanner. I suspect potential issues with the transmission control module (TCM) or communication between the powertrain control module (PCM) and TCM. Specifically, P0700 is a generic transmission code indicating a possible failure in transmission system communication. The presence of P0463 suggests an issue with the fuel system, possibly related to a faulty oxygen sensor or fuel pressure regulation. I'm seeking advice on how to properly diagnose these codes and whether a TCM malfunction—such as loss of power—is likely causing the P0700 code.

Related fault codes
P0300P0463P0700P1684
Comments (3)
Anonymous 2015-10-29 11:45

P0700 is a generic transmission code that typically indicates communication issues between the PCM and TCM. The key dance method, while helpful, is not as reliable as using an actual OBD2 scanner for comprehensive diagnostics. Be sure to check the transmission relay and ensure it's receiving 12 volts of power. Also verify that all related fuses are intact. It's worth noting that a remote starter could interfere with system signals—consider disabling it temporarily if possible.

Anonymous 2015-10-29 18:57

When I connected an OBD2 scanner to my 1999 Chrysler Concorde LXI, the only code returned was P0700. This suggests a potential issue with the transmission control module (TCM) or its communication with the PCM. Could this be due to a TCM malfunction? It's possible that the TCM is not responding properly or isn't receiving power.

Anonymous 2015-10-30 07:56

If there are no specific transmission codes like P074x, it's likely that the PCM is not detecting a signal from the TCM. This absence of communication triggers the P0700 code. The user mentioned 'TCM malfunction'—this may refer to a lack of power or signal rather than a complete hardware failure. Once we confirm proper TCM signal and power, we can address other issues such as misfires (P0300) and fuel system problems (P0463).