DTC P1649 [WL-3]

id0102b8957400

DTC P1649

Injection pump EPROM circuit malfunction

DETECTION CONDITION

•  If PCM cannot access to the injection pump EPROM, the PCM determines that the injection pump EPROM circuit a has malfunction.

POSSIBLE CAUSE

•  Injection pump EPROM malfunction

•  PCM malfunction

•  Connector or terminal malfunction

•  Open circuit between injection pump EPROM terminal (Fuel injection pump connector B) D and PCM terminal 1A

•  Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) F and PCM terminal 2E

•  Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) G and PCM terminal 2L

•  Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) E and PCM terminal 1S

•  Open circuit between injection pump EPROM terminal (Fuel injection pump connector B) H and PCM terminal 1B

DTC P1649	Injection pump EPROM circuit malfunction
DETECTION CONDITION	• If PCM cannot access to the injection pump EPROM, the PCM determines that the injection pump EPROM circuit a has malfunction.
POSSIBLE CAUSE	• Injection pump EPROM malfunction • PCM malfunction • Connector or terminal malfunction • Open circuit between injection pump EPROM terminal (Fuel injection pump connector B) D and PCM terminal 1A • Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) F and PCM terminal 2E • Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) G and PCM terminal 2L • Open or short to ground circuit between injection pump EPROM terminal (Fuel injection pump connector B) E and PCM terminal 1S • Open circuit between injection pump EPROM terminal (Fuel injection pump connector B) H and PCM terminal 1B

Diagnostic procedure

STEP	INSPECTION		ACTION
1	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT? • Clear the DTC. (See AFTER REPAIR PROCEDURE [WL-3].) • Start the engine. • Is the same DTC present?	Yes	Go to the next step.
2		No	Intermittent concern exists. Perform the “INTERMITTENT CONCERN TROUBLESHOOTING”. (See INTERMITTENT CONCERN TROUBLESHOOTING [WL-3].)
3	INSPECT INJECTION PUMP EPROM CONNECTOR FOR POOR CONNECTION • Turn the engine switch to the off position. • Disconnect the injection pump EPROM connector. • Check for poor connection (damaged, pulled-out pins, corrosion, etc.). • Is there a malfunction?	Yes	Repair or replace the terminal, then go to Step 9.
3		No	Go to the next step.
4	INSPECT INJECTION PUMP EPROM POWER CIRCUIT FOR OPEN CIRCUIT • Measure the voltage between fuel injection pump connector B terminal D (wiring harness-side) and body ground. • Is the voltage approx. 5V?	Yes	Go to the next step.
4		No	Repair or replace open wiring harness, then go to Step 9.
5	INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the engine switch to the off position. • Disconnect the PCM connector. • Check for poor connection (damaged, pulled-out pins, corrosion, etc.). • Is there a malfunction?	Yes	Repair or replace the terminal, then go to Step 9.
5		No	Go to the next step.
6	INSPECT INJECTION PUMP EPROM CIRCUIT FOR SHORT TO GROUND • Inspect the following terminals for continuity: ― Between fuel injection pump connector B terminal F and body ground ― Between fuel injection pump connector B terminal G and body ground ― Between fuel injection pump connector B terminal E and body ground • Is there continuity?	Yes	Repair or replace wiring harness, then go to Step 9.
6		No	Go to the next step.
7	INSPECT INJECTION PUMP EPROM CIRCUIT FOR OPEN CIRCUIT • Inspect the following terminals for continuity: ― Between fuel injection pump connector B terminal F and PCM terminal 2E ― Between fuel injection pump connector B terminal G and PCM terminal 2L ― Between fuel injection pump connector B terminal E and PCM terminal 1S ― Between fuel injection pump connector B terminal H and PCM terminal 1B • Is there continuity?	Yes	Go to the next step.
7		No	Repair or replace open wiring harness, then go to Step 9.
8	INSPECT INJECTION PUMP EPROM • Perform injection pump EPROM inspection. (See INJECTION PUMP EPROM INSPECTION [WL-3].) • Is the injection pump EPROM normal?	Yes	The fuel injection pump may have a malfunction. Consult your distributor for the inspection of the fuel injection pump. Go to the next step.
8		No	Consult your distributor for the replacement of the injection pump EPROM. Go to the next step.
9	VERIFY TROUBLESHOOTING OF DTC P1649 COMPLETED • Turn engine switch to OFF and ON (Engine off). • Clear the DTCs from memory using M-MDS. • Start the engine. • Is the same DTC present?	Yes	Replace PCM, then go to the next step.
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE • Perform “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [WL-3].) • Is there any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [WL-3].)
10		No	Troubleshooting completed.