UDS Time Parameters

Session Parameters

S3 _Client

On the client side, the S3_Client parameter defines the time interval for sending periodic Tester Present request messages. This ensures that the server(s) the client communicates with do not exit the current diagnostic session due to inactivity.

Default value:

2000ms

Minimum value:

P2_Client

Maximum value:

S3_Server

S3_Server

On the server side, the S3_Server parameter defines the inactivity time (i.e. the period without any request messages), after which the server shall exit the current diagnostic session and return to the Default Session.

S3_Server = 5000ms

Network Delays

△P2

△P2 is the sum of delays affecting P2 timing parameters in UDS. It consists of:

• △P2 _request – maximum delay from sending a request message to receiving it at the server

• △P2 _response – maximum delay from sending a response message to receiving it at the client

△P2 = △P2_request + △P2_response

△P6

△P6 is the sum of delays affecting P6 timing parameters in UDS. It consists of:

• △P6 _request – maximum delay from sending a request message to receiving it at the server (△P6 _request = △P2 _request)

• △P6 _response – maximum delay from the start of response transmission to full reception at the client

△P6 = △P6_request + △P6_response

Client Side Parameters

P2_Client

P2_Client is the time on the client side from transmitting a request until the start of the first response message (positive or negative, or Response Pending NRC 0x78).

Timeout value:

P2_{Server_max} + △P2 (or greater)

Error handling:

If P2_Client timeout is exceeded, then the reception of the response message shall be aborted.

P2*_Client

P2*_Client is the time on the client side after receiving a Response Pending negative response (NRC 0x78) until the next response is received.

Timeout value:

P2*_{Server_max} + △P2_response (or greater)

Error handling:

If P2*_Client timeout is exceeded, then the reception of the response message shall be aborted.

P3_{Client_Phys}

P3_{Client_Phys} is the time on the client side after sending a physically addressed request message that does not require a response. If the server does respond, this timer does not apply.

Minimum value:

P2_{Server_max} + △P2

P2_Client

Performance requirement:

The client shall assume that the addressed server has received and successfully processed the request, if no response was received within P3_{Client_Phys} time. The client might proceed with sending a following request.

P3_{Client_Func}

P3_{Client_Func} is the waiting time on the client side after sending a functionally addressed request message that does not require a response. If the server does respond, this timer does not apply.

Minimum value:

P2_{Server_max} + △P2

P2_Client

Performance requirement:

The client shall assume that all addressed servers have received and successfully processed the request, if no response was received within P3_{Client_Func} time. The client might proceed with sending a following request.

P6_Client

P6_Client is the time from transmitting a request until the end of the first (and final) response message transmission. If one or more Response Pending messages are sent, then P6*_Client applies instead.

Timeout value:

P2_{Server_max} + △P6 (or greater)

Error handling:

If P6_Client timeout is exceeded, then the reception of the response message shall be aborted.

P6*_Client

P6*_Client is the time from transmitting a request until the end of the final response message, when one or more Response Pending negative responses were sent before the final answer. If the final response is sent immediately, P6_Client applies.

Timeout value:

P2*_{Server_max} + △P6 (or greater)

Error handling:

If P6*_Client timeout is exceeded, then the reception of the response message shall be aborted.

Server Side Parameters

P2_Server

P2_Server is the time after which the server sends the first response (either positive or negative) after receiving a request message.

Minimum value:

0

Maximum value:

specific for the server default: 50ms

Performance requirement:

The server shall send a response (assuming the request requires one) within P2_Server. If the final response is not yet available, the server shall send a negative response with NRC Response Pending (0x78).

P2*_Server

P2*_Server is the additional time allowed for the server to send the final response after issuing a Response Pending (NRC 0x78).

Minimum value:

0

Maximum value:

specific for the server default: 5000ms

Performance requirement:

After sending a negative response with NRC Response Pending (0x78), the server shall provide the next response within P2*_Server. If the final response is still not available, the server shall send another Response Pending (0x78).

P4_Server

P4_Server is the total time from receiving a request until sending the final response. If the server sends Response Pending messages, P2*_Server applies between intermediate responses, but the final response must still be sent within the overall P4_Server limit.

Minimum value:

P2_Server

Maximum value:

specific for the server

Performance requirement:

The server shall send the final response within P4_Server after receiving the request. If the final response is still not available when this time expires, the server shall abort the response message transmission.