What does it mean?
Many vehicles have a control module for the automatic transmission called the Transmission Control Module (TCM). The Engine Control Module (ECM) communicates with the TCM to monitor the automatic transmission for faults. If the TCM detects a fault in the automatic transmission and sets a transmission-related fault code, the ECM is also notified and sets a P0700 in the ECM memory.
This illuminates the Malfunction Indicator Light (MIL) to inform the driver that there is a problem. If this code is present and the MIL is on, it essentially means that there is at least one transmission code set in the TCM memory. P0700 is an informational code only. It does not indicate a direct fault in the engine, only a general fault in the transmission. Further diagnosis is required to identify the transmission fault. This requires a scan tool that will communicate with the transmission module.
Symptoms
Symptoms of a DTC P0700 may include:
- Illumination of the Malfunction Indicator Light (MIL)
- The transmission may exhibit handling issues such as slipping, etc.
Causes
More often than not, the cause of this code is that there is some kind of transmission problem. The TCM has detected the issue and set a code. P0700 means that an error code is stored in the TCM. However, this does not rule out the possibility of a faulty PCM or TCM (unlikely).
Possible Solutions
For a P0700, the only real solution is to acquire a scan tool that will communicate with the transmission control module. Retrieving this code from the TCM will be the first step in repairing the transmission fault.
If the TCM-compatible scan tool does not communicate with the transmission control module, it is a good indication that there may be a problem with the TCM itself.