DTC PZ2128, Loss Of Serial Communications - IRC: Notes

Every 5 seconds, while ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a performance condition signal to Integrated Radio Controller (IRC) indicating system is operating properly. Signal is then transmitted to PZM. DTC PZ2128 will set when PZM does not receive signal from IRC after 3 consecutive monitoring cycles. When DTC PZ2128 is set, PZM will send a class 2 signal to instrument panel cluster to display NO IRC DATA message. DTC PZ2128 will clear when IRC transmits signal to PZM.

If multiple class 2 codes are set as current (i.e., PZ2016, PZ2096, PZ2128, PZ2152, PZ2153), check for short to ground or battery in circuit between IRC and individual control modules.