General Specification Electrical Function gmw3110 General Motors Local Area Network Enhanced Diagnostic Test Mode Specification

8.5.7 Node Verification Procedure. 
Procedure 1: 
1. While not in programming mode, transmit a $20 service request with extra information appended to the 
message resulting in an incorrect length and verify negative response ($7F $20 $12). 
2. Repeat step 1 while programming mode is active and verify that the negative response ($7F $20 $12).is 
sent. 
Procedure 2: 
1. While in programming mode, transmit a service $20 request message using the functional all-nodes CAN 
Identifier ($101) + all-nodes extended address ($FE). Verify that there is no response sent. 
 
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GMW3110 
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Procedure 3: 
1. While not in programming mode, transmit a service $20 request message while periodic DPIDs are 
scheduled. Verify the positive response and that the scheduled messages are halted. 
2. If the node supports dynamic DPIDs, define a dynamic message number via service $2C, and configure 
the node to schedule the message periodically via service $AA. Verify that periodic responses are 
received. Next transmit a service $20 request to the node and verify that the just-defined periodic 
message(s) are halted. 
3. Repeat the $AA request to schedule the dynamically defined message, and verify that the format of the 
dynamically defined message was not lost after the service $20 request. 
Procedure 4: 
(Valid if the send on change DTC logic is supported by the node).
 
1. While not in programming mode, transmit a service $20 request message while the DTC send-on-change 
algorithm is activated. Verify the positive response and that the updated DTC count information is no 
longer reported by the node. (This can be done by causing a code to transition to a state that satisfies the 
send-on-change DTC status mask, and verifying that no information is reported by the node.) 
Procedure 5: 
1. While not in programming mode, transmit a service $20 request message while tester-requested device 
controls are active. Verify the positive response and that full control of inputs/outputs is returned to the 
ECU. 
Procedure 6: 
(Valid if the SPS security access levels of the $27 service are supported). 
1. While not in programming mode, transmit a service $20 request message to a node whose security is 
currently unlocked via service $27 SecurityAccess (with Manufacturers Enable Counter set to $00 and 
vulnerability flag not $FF). After the $60 positive response, verify via a service $27 $01 request that the 
node becomes locked (seed != $0000). 
2. While not in programming mode, transmit a service $20 request to a node with a non-zero Manufacturers 
Enable Counter (MEC) and vulnerability flag not equal to $FF. After the $60 positive response, verify via a 
service $27 $01 request that the node unlocks (seed = $0000). 
3. While not in programming mode, transmit a service $20 request to a node with a Vulnerability Flag set to 
$FF (if applicable) and MEC set to $00. After the $60 positive response, verify via a service $27 $01 
request that the node unlocks (seed = $0000).