Communication Error

It is possible to receive a communication error from a WDS or equivalent tester when initiating a diagnostic test or accessing PIDs. The communication error can be caused by operator error, the vehicle wiring, connectors, the PCM or other control modules connected to the DLC wiring. The PCM will respond to a WDS or equivalent tester whenever the tool requests a test. These are not DTCs. Listed below are numeric codes and generic descriptions that a scan tool may display when trying to perform some PCM operations. It is possible to get other numeric codes not listed. For a complete list of communication response codes, See Society of Automotive Engineers (SAE) document J2190 enhanced E/E Diagnostic Test Modes. Some are normal responses to valid requests. The others are communication error responses. If the tool displays any of the communication error responses check scan tool connections, cable/adapters and entry of vehicle information.

Numeric Code	Generic Description	Expanded Description
NORMAL PCM RESPONSES
00	General affirmative	PCM received a valid request from scan tool.
62	Normal exit without test results	PCM performed a valid request from the WDS or equivalent tester and has no results (i.e., KOEO Self-Test performed with no DTCs recorded).
61	Normal exit with test results	PCM performed a valid request from the WDS or equivalent tester and has results (i.e., KOEO self-test was performed and a DTC was recorded).
ABNORMAL PCM RESPONSES
10	General reject	PCM will not respond to request.
11	Mode not supported	PCM is not capable of performing a requested test (i.e., turn injectors on and off).
12	Invalid data format	An unrecognized character is inserted into a string of data.
21	PCM is busy at time of request	PCM is already performing a test at the time another test is requested.
22	Entry conditions not correct	Usually operator error (i.e., engine not running or in gear when requesting KOER Self-Test).
23	Asked for results before done	A message was received by the PCM but the PCM is not ready to respond.
50	Upload not accepted	A request for information or a test cannot be accomplished due to a fault condition.
63	Abnormal exit with results	While PCM is performing a test, an error occurred, but PCM has results (i.e., DTCs).
64	Abnormal exit without results	While PCM is performing a test, an error occurred and no results are available (i.e., aborted KOER Self-Test before DTC was recorded).