DTC 135

DTC 135 Chart:

HVAC Programmer Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) uses the serial data line (CKT 800) to communicate with various other components and systems within the vehicle. If the PCM does not receive data from the HVAC programmer, the PCM will store DTC 135 indicating loss of communication with the HVAC system.

DTC 135 WILL SET WHEN
- DTC 12 is not set.
- Engine running for over 20 seconds.
- PCM has detected an HVAC communication error for 10 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
With a current DTC 135 stored, the PCM will not be able to communicate with the HVAC programmer. DTC 135 does not illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).

DTC 135 WILL CLEAR WHEN
The fault no longer exists.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks to see if the HVAC programmer is able to transmit data and ensures that CKT 800 to the HVAC programmer is not open.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.
Check for:

Poor connection or damaged harness
Inspect vehicle wiring harness, for an open or short to ground in CKT 800, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

Intermittent test
Observe HVAC data on the Tech 1 while moving harness and related connectors. If failure is induced, Tech 1 data will stop updating. This may help to isolate the location of the malfunction.

If, while the vehicle is running, the ignition key is turned to the crank position, the following DTC(s) may set 133, 134, 135 and 136.