P1606

P : DTC P1606. PCM RELAY.

P1 : CHECK THE PCM CONTROL RELAY

1. Turn the ignition switch to the ON position.

Does the PCM relay make an audible click?
Yes
Goto P2

No
Goto P6

P2 : CHECK FOR POWER SUPPLY FROM THE PCM CONTROL RELAY

1. Measure the voltage between the PCM control relay JB34 pin 131 and GROUND.

Is the voltage less than 10 volts?
Yes
Goto P3

No
REPAIR the circuit from the PCM control relay to the PCM. For additional information, refer to wiring diagrams. CLEAR the DTC. TEST the system for normal operation.

P3 : CHECK FUSE 9 IN THE ENGINE COMPARTMENT FUSE BOX

1. Check the fuse.

Is the fuse OK?
Yes
Goto P4

No
INSTALL a new fuse. Check the circuit for cause of fuse failure. CLEAR the DTC. TEST the system for normal operation.

P4 : CHECK THE POWER SUPPLY TO FUSE 9 IN THE ENGINE COMPARTMENT FUSE BOX

1. Measure the voltage between Fuse 9 electrical connector JB34 pin 75 and GROUND.

Is the voltage less than 10 volts?
Yes
REPAIR the circuit from the battery positive to the engine compartment fuse box. CLEAR the DTC. TEST the system for normal operation.

No
Goto P5

P5 : CHECK THE POWER SUPPLY FROM FUSE 9 IN THE ENGINE COMPARTMENT FUSE BOX TO THE PCM CONTROL RELAY

1. Measure the voltage between the PCM control relay electrical connector JB34 pin 132 and GROUND.

Is the voltage less than 10 volts?
Yes
REPAIR the circuit from the engine compartment fuse box to the PCM control relay. CLEAR the DTC. TEST the system for normal operation.

No
INSTALL a new PCM control relay. For additional information, refer to the electrical guide. CLEAR the DTC. TEST the system for normal operation.

P6 : CHECK FUSE 31 OF THE ENGINE COMPARTMENT FUSE BOX

1. Check the fuse.

Is the fuse OK?
Yes
Goto P7

No
Goto P10

P7 : CHECK POWER SUPPLY TO THE PCM CONTROL RELAY FROM FUSE 31 OF THE ENGINE COMPARTMENT FUSE BOX

1. Measure the voltage between PCM relay electrical connector JB34 pin 133 and GROUND.

Is the voltage less than 10 volts?
Yes
Goto P8

No
Goto P12

P8 : CHECK CONTINUITY OF THE PCM CONTROL RELAY GROUND CIRCUIT

1. Disconnect the PCM electrical connector EN16.
2. Remove the PCM control relay from the engine compartment fuse box.
3. Measure the resistance between the PCM electrical connector EN16 pin 40 and JB34 pin 134 of the engine compartment fuse box.

Is the resistance less than 5 ohms?
Yes
Goto P9

No
REPAIR the circuit. For additional information, refer to wiring diagrams. CLEAR the DTC. TEST the system for normal operation.
This circuit includes the power distribution fuse box and the EMS relay and diode

P9 : CHECK CONTINUITY OF THE PCM CONTROL RELAY WINDING

1. Measure the resistance of the PCM control relay winding between pins 1 and 2 of the PCM control relay.

Is the resistance less than 60 ohms?
Yes
INSTALL a new PCM control relay. CLEAR the DTC. TEST the system for normal operation.

No
INSTALL a new PCM. Before replacing a PCM, contact Dealer technical support. CLEAR the DTC. TEST the system for normal operation.

P10 : CHECK FUSE 31 OF THE ENGINE COMPARTMENT FUSE BOX FOR A SHORT TO GROUND

1. Measure the resistance between electrical connector JB34 pin 83 of the engine compartment fuse box and GROUND.

Is the resistance less than 10,000 ohms?
Yes
REPAIR short to GROUND between the engine compartment fuse box and the PCM control relay. CLEAR the DTC. TEST the system for normal operation.

No
INSTALL a new fuse. CLEAR the DTC. TEST the system for normal operation.

P11 : CHECK FUSE 9 OF THE ENGINE COMPARTMENT FUSE BOX FOR A SHORT TO GROUND

1. Measure the resistance between electrical connector JB34 pin 132 of the engine compartment fuse box and GROUND.

Is the resistance less than 10,000 ohms?
Yes
REPAIR short to ground between the engine compartment fuse box and the PCM control relay. CLEAR the DTC. TEST the system for normal operation.

No
INSTALL a new fuse. CLEAR the DTC. TEST the system for normal operation.

P12 : CHECK THE PCM CONTROL RELAY DIODE

1. Remove the PCM control relay diode from the engine compartment fuse box.
2. Measure the continuity of PCM control relay diode.

Is the resistance less than 5 ohms?
Yes
Possible intermittent fault. Recheck DTCs.

No
INSTALL a new PCM control relay diode. Make sure that the PCM control relay diode is installed correctly. For additional information, refer to the wiring diagrams. CLEAR the DTC. TEST the system for normal operation.