ABS CODE 61 DIAGNOSIS/INFO SERVICE (EBCM) & (PMV)

SUBJECT: ABS CODE 61

MODELS AFFECTED: 1991 DE VILLES AND FLEETWOODS

ABS code 61 will set when the Electronic Brake Control Module (EBCM) determines the Pressure Modulator Valve (PMV) pump motor is not running (no voltage at EBCM terminals 31 and 49) after the EBCM has grounded the ABS pump motor relay.

To begin diagnosis of this code, first determine if the pump motor runs by performing the bleed procedure with the Tech 1. If the pump motor runs, motor run sensor circuit exists. Following Chart F in Section 5E1 should effectively diagnose most vehicles.

An intermittent setting of ABS code 61 may occur due to one of the following:

1. Circuit 1292 or 1293 (pump motor sense circuits) may protrude from the conduit, chafe on the ELC bracket, and set a code 61. These circuits are in the ABS harness located in the engine compartment which is routed between the left strut tower and the ELC compressor bracket.

2. It is also possible for the pump motor run sensor to short to the PMV motor's housing. To determine this the pump motor should be disconnected and an ohmmeter used to measure the resistance from either pump motor connector pin D or F to the motor housing. The resistance should be greater than 2000 ohms.

There is a label on the PMV pump motor housing bearing a 16-digit serial number PMV pump motors after breakpoint 0204008040045970 have had the inside wall of the pump motor insulates with a mesh tape. This isolation tape will prevent the sensor from contacting the walls of the pump motor and shorting to ground. The revised pump motor, P/N 25559182, is in current production.

Parts are currently available from GMSPO.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.