QB: Diagnostic Trouble Code (DTC) P0603/P1605/P1633

QB: Introduction See: QB: Diagnostic Trouble Code (DTC) P0603/P1605/P1633 - Introduction

QB1 CHECK BATTERY TERMINALS

Note: If KAPWR is interrupted to the PCM (that is, when a breakout box is installed or the battery is disconnected), DTC P0603/P1605 can be generated on the first power-up.

• Inspect the battery cables for loose connections, corrosion.

Are the battery terminal connections in good condition?
Yes

• KEY OFF. Battery terminals are OK. GO to QB2

.

No

• REPAIR battery terminals as necessary.

QB2 INSPECT ENGINE COMPARTMENT FOR PROPER WIRE ROUTING

• Inspect Electronic Engine Control (EC) System wiring for proximity to ignition components or wires.

Is wiring too close to ignition components or wires?
Yes

• REROUTE as necessary.

No

• Engine compartment wire routing is OK. GO to QB3

.

QB3 CHECK KEEP ALIVE POWER (KAPWR) TO PCM

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Measure voltage between KAPWR circuit at the PCM harness connector and ground.
• While observing digital multimeter, grasp the Electronic EC harness and wiggle, shake or bend a small section while working from the PCM to the dash panel.

Does the voltage reading indicate less than 10.5 volts?
Yes

• ISOLATE and REPAIR open circuit.

No

• No open in KAPWR harness circuit detected. GO to QB4

.

QB4 CHECK FOR REPEAT OF DTC P0603/P1605/P1633

• Reconnect PCM.
• Start engine and allow it to reach operating temperature.
• Run Key On Engine Off Self-Test.
• Retrieve Continuous Memory DTCs.

Is DTC P0603, P1605 or P1633 present?
Yes

• REPLACE the PCM.

No

• REPAIR other DTCs as necessary. If none, testing is complete.