STEP/SEQUENCE RESULT WHAT TO DO NEXT TM 9-2320-363-20-1 Section 4 TROUBLESHOOTING CHARTS E. FLASH CODE: 42 J1587 CODE: S21 1 - TOO FEW SRS (MISSING SRS) NOTE - This chart is only to be used if: 1) All basic mechanical checks and physical inspections have been performed with no problem found, and 2) Diagnosis of DDEC-III was started at step Start-1, pg 3-345.41 and you have now been referred here. 42-1 Resistance Check Turn ignition off. Less than or Go to 42-2. Disconnect engine harness equal to 200 ohms. connector at ECM. Read resistance between socket Greater than Go to 42-3. S1 and S2 on engine harness 200 ohms or open. connector. 42-2 Check for Short Disconnect SRS connector. Less than or A short exists where resistance Read resistance between sockets equal to 10,000 ohms was less than 10,000 ohms. S1 and S2 on engine harness on any reading Repair short.  Then go to 42-30 connector. Also read resistance between socket S1 and ground, then Greater than Go to 42-4. between socket S2 and ground. 10,000 ohms or open on all readings. 42-3 Open SRS Line Check Disconnect SRS connector and Less than or Go to 42-4. install a jumper wire between equal to 5 ohms. sockets A and B of the SRS harness connector. Greater than Signal line (ckt #111) or return Read resistance  between sockets 5 ohms or open. line (ckt #112) is open. S1 and S2 on the engine harness Repair open.  Then go to 42-30. connector. 42-4 Check SRS Resistance Read resistance of SRS across Less than Go to 42-12. sensor connector pins A and B. 100 ohms From 100 to Go to 42-5. 200 ohms. Greater than Go to 42-12. 200 ohms. Change 3  3-345.323