Scan Tool Does Not Communicate with Engine Control Module
SCAN TOOL DOES NOT COMMUNICATE WITH ENGINE CONTROL MODULE
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Was the Data Link Communications Diagnostic System Check performed? | -- | Go to Step 2 | Diagnostic System Check - Data Link Communications |
| 2 | Attempt to establish communication with the other modules connected to the circuit. * Instrument Cluster * Memory Seat Module (MSM) * Transmission Control Module (TCM) Does the scan tool communicate with the other modules? |
-- | Go to Step 3 | Go to Step 20 |
| 3 | 1. Disconnect ECM connector C2. 2. Test the serial data circuit, between ECM connector C2 terminal 53 and the data link connector (DLC) terminal 7, for an open. Did you find an open in the serial data circuit? |
-- | Go to Step 6 | Go to Step 5 |
| 4 | 1. Disconnect the ECM connector C2. 2. Attempt to communicate with the other modules. Does the scan tool communicate with the other modules? |
-- | Go to Step 7 | Go to Step 8 |
| 5 | Inspect for poor connections at ECM connector C2 terminal 53. Refer to TESTING FOR INTERMITTENTS & POOR CONNECTIONS Did you find and correct the poor connection condition? |
-- | Go to Step 9 | Go to Step 10 |
| 6 | Repair the open in CKT XM100. Is the repair complete? |
-- | Go to Step 9 | -- |
| 7 | Replace the ECM. Is the replacement complete? |
-- | Go to Step 9 | -- |
| 8 | 1. Reconnect the ECM. 2. Disconnect connector C1 from the MSM. 3. Attempt to communicate with the other modules. Does the scan tool communicate with the other modules? |
-- | Go to Step 12 | Go to Step 13 |
| 9 | Attempt to establish communications with the ECM. Does the scan tool communicate with the ECM? |
-- | System OK | -- |
| 10 | 1. Inspect and test the ECM battery and ignition positve voltage circuits. 2. Inspect and test the ECM ground wire at the ECM mounting plate. 3. Inspect and test the operation of the Engine Controls Power Relay (K43). Refer to Engine Controls Power Relay Circuit Diagnosis 4. Make necessary repairs. Did you find and correct any conditions? |
-- | Go to Step 9 | Go to Step 7 |
| 11 | Replace the TCM. Is the replacement complete? |
-- | Go to Step 9 | -- |
| 12 | Replace the MSM. Is the replacement complete? |
-- | Go to Step 9 | -- |
| 13 | 1. Reconnect the MSM. 2. Disconnect the TCM connector. 3. Attempt to communicate with the other modules. Does the scan tool communicate with the other modules? |
-- | Go to Step 11 | Go to Step 14 |
| 14 | 1. Reconnect the TCM. 2. Disconnect the instrument cluster connector. 3. Attempt to communicate with the other modules. Does the scan tool communicate with the other modules? |
-- | Go to Step 15 | Go to Step 16 |
| 15 | Replace the instrument cluster. Is the replacement complete? |
-- | Go to Step 9 | -- |
| 16 | 1. Disconnect each module on the serial data circuit (DLC terminal 7). 2. Test the serial data circuit, of the DLC, for a short to ground 3. Test between terminal 7 and the following terminals at each module: * ECM connector C2 terminal 53 * Instrument Cluster connector terminal 24 * Memory Seat Module connector C1 terminal 6 * TCM connector terminal 51 Did you find a short to ground in the serial data circuit? |
-- | Go to Step 17 | Go to Step 18 |
| 17 | Locate and repair the short to ground in the serial data circuit. Is the repair complete? |
-- | Go to Step 9 | -- |
| 18 | Test the serial data circuit, of the DLC, for a short to voltage between terminal 7 and each module. (Turn ON the ignition, leaving the engine OFF, when testing for a short to voltage.) * ECM connector C2 terminal 53 * Instrument Cluster connector terminal 24 * Memory Seat Module connector C1 terminal 6 * TCM connector terminal 51 Did you find a short to voltage in the serial data circuit? |
-- | Go to Step 19 | Go to Step 21 |
| 19 | Locate and repair the short to voltage in the serial data circuit. Is the repair complete? |
-- | Go to Step 9 | -- |
| 20 | 1. Turn OFF the ignition. 2. Disconnect the scan tool from the data link connector (DLC). 3. Inspect for poor connections/terminal tension at the DLC terminal 7. Refer to TESTING FOR INTERMITTENTS & POOR CONNECTIONS Did you find and correct a poor connection condition? |
-- | Go to Step 2 | Go to Step 4 |
| 21 | Test the serial data circuit, of the DLC, for an open between terminal 7 and each module. * ECM connector C2 terminal 53 * Instrument Cluster connector terminal 24 * Memory Seat Module connector C1 terminal 6 * TCM connector terminal 51 Did you find an open in the serial data circuit? |
-- | Go to Step 9 | -- |