Diagnostic Aids

DTCs that may cause a no-start should be diagnosed first:

• "U" type communications DTCs.
• BCM or ECM PassLock® security system (DTCs P1630, P1631, P1632 or B1372).
• ECM internal fault DTCs.

With ignition, and engine off, ensure ECT, MAP and TP sensor readings on scan tool are normal. MAP sensor reading should be 14-15 psi (.98-1.1 kg/cm² ). The ECT and IAT sensor should be within 10°F (4°C) of each other with vehicle sitting overnight. A skewed sensor may cause a hard or no-start condition.

If no RPM from the CKP sensor is detected, spark and fuel will not be turned on. The signal from the CKP sensor is sent to the ECM. When engine is cranking, the scan tool CKP ACTIVE COUNTER should continuously count up to 255 then reset to zero. Check for flooded engine.

Check the following fuses in the underhood fuse/relay block. These fuses will cause a no-start, if open:

• POWERTRAIN (10A)
• FUEL PUMP (10A)
• IGN 1/2 (30A)
• IGN/INJ (15A)
• ECM/TCM (10A)
• ETC (15A)
• BCM (10A)
• BCM/Cluster (10A)